201
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Salem R, Soliman M, Fergala A, Audette GF, ElDyasti A. Screening for Methane Utilizing Mixed Communities with High Polyhydroxybutyrate (PHB) Production Capacity Using Different Design Approaches. Polymers (Basel) 2021; 13:1579. [PMID: 34069256 PMCID: PMC8157138 DOI: 10.3390/polym13101579] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 05/08/2021] [Accepted: 05/11/2021] [Indexed: 12/04/2022] Open
Abstract
With the adverse environmental ramifications of the use of petroleum-based plastic outweighing the challenges facing the industrialization of bioplastics, polyhydroxyalkanoate (PHA) biopolymer has gained broad interest in recent years. Thus, an efficient approach for maximizing polyhydroxybutyrate (PHB) polymer production in methanotrophic bacteria has been developed using the methane gas produced in the anaerobic digestion process in wastewater treatment plants (WWTPS) as a carbon substrate and an electron donor. A comparison study was conducted between two experimental setups using two different recycling strategies, namely new and conventional setups. The former setup aims to recycle PHB producers into the system after the PHB accumulation phase, while the latter recycles the biomass back into the system after the exponential phase of growth or the growth phase. The goal of this study was to compare both setups in terms of PHB production and other operational parameters such as growth rate, methane uptake rate, and biomass yield using two different nitrogen sources, namely nitrate and ammonia. The newly proposed setup is aimed at stimulating PHB accumulating type II methanotroph growth whilst enabling other PHB accumulators to grow simultaneously. The success of the proposed method was confirmed as it achieved highest recorded PHB accumulation percentages for a mixed culture community in both ammonia- and nitrate-enriched media of 59.4% and 54.3%, respectively, compared to 37.8% and 9.1% for the conventional setup. Finally, the sequencing of microbial samples showed a significant increase in the abundance of type II methanotrophs along with other PHB producers, confirming the success of the newly proposed technique in screening for PHB producers and achieving higher PHB accumulation.
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Affiliation(s)
- Rana Salem
- Civil Engineering Department, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada; (R.S.); (M.S.)
| | - Moomen Soliman
- Civil Engineering Department, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada; (R.S.); (M.S.)
| | - Ahmed Fergala
- Department of Biotechnology, Delft University of Technology, Mekelweg 5, 2628 CD Delft, The Netherlands;
| | - Gerald F. Audette
- Chemistry Department, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada;
| | - Ahmed ElDyasti
- Civil Engineering Department, York University, 4700 Keele Street, Toronto, ON M3J 1P3, Canada; (R.S.); (M.S.)
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202
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Evolution of default genetic control mechanisms. PLoS One 2021; 16:e0251568. [PMID: 33984070 PMCID: PMC8118313 DOI: 10.1371/journal.pone.0251568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 04/28/2021] [Indexed: 11/19/2022] Open
Abstract
We present a model of the evolution of control systems in a genome under environmental constraints. The model conceptually follows the Jacob and Monod model of gene control. Genes contain control elements which respond to the internal state of the cell as well as the environment to control expression of a coding region. Control and coding regions evolve to maximize a fitness function between expressed coding sequences and the environment. The model was run 118 times to an average of 1.4∙106 ‘generations’ each with a range of starting parameters probed the conditions under which genomes evolved a ‘default style’ of control. Unexpectedly, the control logic that evolved was not significantly correlated to the complexity of the environment. Genetic logic was strongly correlated with genome complexity and with the fraction of genes active in the cell at any one time. More complex genomes correlated with the evolution of genetic controls in which genes were active (‘default on’), and a low fraction of genes being expressed correlated with a genetic logic in which genes were biased to being inactive unless positively activated (‘default off’ logic). We discuss how this might relate to the evolution of the complex eukaryotic genome, which operates in a ‘default off’ mode.
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203
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Schulz C, Castillo RG, Pantazis DA, DeBeer S, Neese F. Structure-Spectroscopy Correlations for Intermediate Q of Soluble Methane Monooxygenase: Insights from QM/MM Calculations. J Am Chem Soc 2021; 143:6560-6577. [PMID: 33884874 PMCID: PMC8154522 DOI: 10.1021/jacs.1c01180] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Indexed: 12/22/2022]
Abstract
The determination of the diiron core intermediate structures involved in the catalytic cycle of soluble methane monooxygenase (sMMO), the enzyme that selectively catalyzes the conversion of methane to methanol, has been a subject of intense interest within the bioinorganic scientific community. Particularly, the specific geometry and electronic structure of the intermediate that precedes methane binding, known as intermediate Q (or MMOHQ), has been debated for over 30 years. Some reported studies support a bis-μ-oxo-bridged Fe(IV)2O2 closed-core conformation Fe(IV)2O2 core, whereas others favor an open-core geometry, with a longer Fe-Fe distance. The lack of consensus calls for a thorough re-examination and reinterpretation of the spectroscopic data available on the MMOHQ intermediate. Herein, we report extensive simulations based on a hybrid quantum mechanics/molecular mechanics approach (QM/MM) approach that takes into account the complete enzyme to explore possible conformations for intermediates MMOHox and MMOHQ of the sMMOH catalytic cycle. High-level quantum chemical approaches are used to correlate specific structural motifs with geometric parameters for comparison with crystallographic and EXAFS data, as well as with spectroscopic data from Mössbauer spectroscopy, Fe K-edge high-energy resolution X-ray absorption spectroscopy (HERFD XAS), and resonance Raman 16O-18O difference spectroscopy. The results provide strong support for an open-core-type configuration in MMOHQ, with the most likely topology involving mono-oxo-bridged Fe ions and alternate terminal Fe-oxo and Fe-hydroxo groups that interact via intramolecular hydrogen bonding. The implications of an open-core intermediate Q on the reaction mechanism of sMMO are discussed.
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Affiliation(s)
- Christine
E. Schulz
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Rebeca G. Castillo
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Dimitrios A. Pantazis
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
| | - Serena DeBeer
- Max
Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Frank Neese
- Max-Planck-Institut
für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany
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204
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Kumar M, Yadav AN, Saxena R, Rai PK, Paul D, Tomar RS. Novel methanotrophic and methanogenic bacterial communities from diverse ecosystems and their impact on environment. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2021. [DOI: 10.1016/j.bcab.2021.102005] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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205
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do Carmo Linhares D, Saia FT, Duarte RTD, Nakayama CR, de Melo IS, Pellizari VH. Methanotrophic Community Detected by DNA-SIP at Bertioga's Mangrove Area, Southeast Brazil. MICROBIAL ECOLOGY 2021; 81:954-964. [PMID: 33392629 DOI: 10.1007/s00248-020-01659-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 12/03/2020] [Indexed: 06/12/2023]
Abstract
Methanotrophic bacteria can use methane as sole carbon and energy source. Its importance in the environment is related to the mitigation of methane emissions from soil and water to the atmosphere. Brazilian mangroves are highly productive, have potential to methane production, and it is inferred that methanotrophic community is of great importance for this ecosystem. The scope of this study was to investigate the functional and taxonomic diversity of methanotrophic bacteria present in the anthropogenic impacted sediments from Bertioga´s mangrove (SP, Brazil). Sediment sample was cultivated with methane and the microbiota actively involved in methane oxidation was identified by DNA-based stable isotope probing (DNA-SIP) using methane as a labeled substrate. After 4 days (96 h) of incubation and consumption of 0.7 mmol of methane, the most active microorganisms were related to methanotrophs Methylomonas and Methylobacter as well as to methylotrophic Methylotenera, indicating a possible association of these bacterial groups within a methane-derived food chain in the Bertioga mangrove. The abundance of genera Methylomonas, able to couple methane oxidation to nitrate reduction, may indicate that under low dissolved oxygen tensions, some aerobic methanotrophs could shift to intraerobic methane oxidation to avoid oxygen starvation.
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Affiliation(s)
- Débora do Carmo Linhares
- Laboratory of Industrial Biotechnology, Institute for Technological Research of São Paulo, 05508-901, São Paulo, SP, Brazil.
- Department of Biological Oceanography, Oceanographic Institute, University of Sao Paulo, Praça do Oceanográfico, 191, 05508-120, Butantã, São Paulo-SP, Brazil.
| | - Flávia Talarico Saia
- Institute of Marine Sciences, Federal University of São Paulo, Av. Dr. Carvalho de Mendonça, 144, Encruzilhada, Santos, SP, 11070-102, Brazil
| | - Rubens Tadeu Delgado Duarte
- Laboratory of Molecular Ecology and Extremophiles, Department of Microbiology, Immunology and Parasitology, Federal University of Santa Catarina, Florianópolis, SC, 88040-900, Brazil
| | - Cristina Rossi Nakayama
- Institute of Environmental, Chemical and Pharmaceutical Sciences, Federal University of São Paulo, Rua São Nicolau, 210, Diadema, SP, 09913-030, Brazil
| | | | - Vivian Helena Pellizari
- Department of Biological Oceanography, Oceanographic Institute, University of Sao Paulo, Praça do Oceanográfico, 191, 05508-120, Butantã, São Paulo-SP, Brazil
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206
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Kadnikov VV, Mardanov AV, Beletsky AV, Grigoriev MA, Karnachuk OV, Ravin NV. Thermophilic Chloroflexi Dominate in the Microbial Community Associated with Coal-Fire Gas Vents in the Kuznetsk Coal Basin, Russia. Microorganisms 2021; 9:microorganisms9050948. [PMID: 33924824 PMCID: PMC8146126 DOI: 10.3390/microorganisms9050948] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/23/2021] [Accepted: 04/24/2021] [Indexed: 01/12/2023] Open
Abstract
Thermal ecosystems associated with areas of underground burning coal seams are rare and poorly understood in comparison with geothermal objects. We studied the microbial communities associated with gas vents from the coal-fire in the mining wastes in the Kemerovo region of the Russian Federation. The temperature of the ground heated by the hot coal gases and steam coming out to the surface was 58 °C. Analysis of the composition of microbial communities revealed the dominance of Ktedonobacteria (the phylum Chloroflexi), known to be capable of oxidizing hydrogen and carbon monoxide. Thermophilic hydrogenotrophic Firmicutes constituted a minor part of the community. Among the well-known thermophiles, members of the phyla Aquificae, Deinococcus-Thermus and Bacteroidetes were also found. In the upper ground layer, Acidobacteria, Verrucomicrobia, Actinobacteria, Planctomycetes, as well as Proteobacteria of the alpha and gamma classes, typical of soils, were detected; their relative abundancies decreased with depth. The phylum Verrucomicrobia was dominated by Candidatus Udaeobacter, aerobic heterotrophs capable of generating energy through the oxidation of hydrogen present in the atmosphere in trace amounts. Archaea made up a small part of the communities and were represented by thermophilic ammonium-oxidizers. Overall, the community was dominated by bacteria, whose cultivated relatives are able to obtain energy through the oxidation of the main components of coal gases, hydrogen and carbon monoxide, under aerobic conditions.
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Affiliation(s)
- Vitaly V. Kadnikov
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (V.V.K.); (A.V.M.); (A.V.B.)
| | - Andrey V. Mardanov
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (V.V.K.); (A.V.M.); (A.V.B.)
| | - Alexey V. Beletsky
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (V.V.K.); (A.V.M.); (A.V.B.)
| | - Mikhail A. Grigoriev
- Laboratory of Biochemistry and Molecular Biology, Tomsk State University, 634050 Tomsk, Russia; (M.A.G.); (O.V.K.)
| | - Olga V. Karnachuk
- Laboratory of Biochemistry and Molecular Biology, Tomsk State University, 634050 Tomsk, Russia; (M.A.G.); (O.V.K.)
| | - Nikolai V. Ravin
- Institute of Bioengineering, Research Center of Biotechnology of the Russian Academy of Sciences, 119071 Moscow, Russia; (V.V.K.); (A.V.M.); (A.V.B.)
- Correspondence:
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207
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Enzymes of an alternative pathway of glucose metabolism in obligate methanotrophs. Sci Rep 2021; 11:8795. [PMID: 33888823 PMCID: PMC8062543 DOI: 10.1038/s41598-021-88202-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 04/06/2021] [Indexed: 11/09/2022] Open
Abstract
Aerobic methanotrophic bacteria utilize methane as a growth substrate but are unable to grow on any sugars. In this study we have shown that two obligate methanotrophs, Methylotuvimicrobium alcaliphilum 20Z and Methylobacter luteus IMV-B-3098, possess functional glucose dehydrogenase (GDH) and gluconate kinase (GntK). The recombinant GDHs from both methanotrophs were homotetrameric and strongly specific for glucose preferring NAD+ over NADP+. GDH from Mtm. alcaliphilum was most active at pH 10 (Vmax = 95 U/mg protein) and demonstrated very high Km for glucose (91.8 ± 3.8 mM). GDH from Mb. luteus was most active at pH 8.5 (Vmax = 43 U/mg protein) and had lower Km for glucose (16 ± 0.6 mM). The cells of two Mtm. alcaliphilum double mutants with deletions either of the genes encoding GDH and glucokinase (gdh─/glk─) or of the genes encoding gluconate kinase and glucokinase (gntk─/glk─) had the lower glycogen level and the higher contents of intracellular glucose and trehalose compared to the wild type strain. The gntk─/glk─ knockout mutant additionally accumulated gluconic acid. These data, along with bioinformatics analysis, demonstrate that glycogen derived free glucose can enter the Entner–Doudoroff pathway or the pentose phosphate cycle in methanotrophs, bypassing glycolysis via the gluconate shunt.
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208
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Lim SJ, Davis B, Gill D, Swetenburg J, Anderson LC, Engel AS, Campbell BJ. Gill microbiome structure and function in the chemosymbiotic coastal lucinid Stewartia floridana. FEMS Microbiol Ecol 2021; 97:6168404. [PMID: 33705534 DOI: 10.1093/femsec/fiab042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 03/09/2021] [Indexed: 11/14/2022] Open
Abstract
Lucinid bivalves harbor environmentally acquired, chemosynthetic, gammaproteobacterial gill endosymbionts. Lucinid gill microbiomes, which may contain other gammaproteobacterial and/or spirochete taxa, remain under-sampled. To understand inter-host variability of the lucinid gill microbiome, specifically in the bacterial communities, we analyzed the microbiome content of Stewartia floridana collected from Florida. Sampled gills contained a monospecific gammaproteobacterial endosymbiont expressing lithoautotrophic, mixotrophic, diazotrophic and C1 compound oxidation-related functions previously characterized in similar lucinid species. Another low-abundance Spirochaeta-like species in ∼72% of the sampled gills was most closely related to Spirochaeta-like species in another lucinid Phacoides pectinatus and formed a clade with known marine Spirochaeta symbionts. The spirochete expressed genes were involved in heterotrophy and the transport of sugars, amino acids, peptides and other substrates. Few muscular and neurofilament genes from the host and none from the gammaproteobacterial and spirochete symbionts were differentially expressed among quadrats predominantly covered with seagrass species or 80% bare sand. Our results suggest that spirochetes are facultatively associated with S. floridana, with potential scavenging and nutrient cycling roles. Expressed stress- and defense-related functions in the host and symbionts also suggest species-species communications, which highlight the need for further study of the interactions among lucinid hosts, their microbiomes and their environment.
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Affiliation(s)
- Shen Jean Lim
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Brenton Davis
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Danielle Gill
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - John Swetenburg
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
| | - Laurie C Anderson
- Department of Geology and Geological Engineering, South Dakota School of Mines & Technology, Rapid City, SD 57701, USA
| | - Annette Summers Engel
- Department of Earth and Planetary Sciences, University of Tennessee Knoxville, Knoxville, TN 37920, USA
| | - Barbara J Campbell
- Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA
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209
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Cordova-Gonzalez A, Birgel D, Kappler A, Peckmann J. Variation of salinity and nitrogen concentration affects the pentacyclic triterpenoid inventory of the haloalkaliphilic aerobic methanotrophic bacterium Methylotuvimicrobium alcaliphilum. Extremophiles 2021; 25:285-299. [PMID: 33866428 PMCID: PMC8102298 DOI: 10.1007/s00792-021-01228-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Accepted: 04/01/2021] [Indexed: 11/30/2022]
Abstract
The occurrence and activity of aerobic methanotrophs are influenced by environmental conditions, including pH, temperature, salinity, methane and oxygen concentrations, and nutrient availability. Aerobic methanotrophs synthesize a variety of lipids important for cell functions. However, culture-based experiments studying the influence of environmental parameters on lipid production by aerobic methanotrophs are scarce. Such information is crucial to interpret lipid patterns of methanotrophic bacteria in the environment. In this study, the alkaliphilic strain Methylotuvimicrobium alcaliphilum was cultivated under different salinities and different nitrate concentrations to assess the effect of changing conditions on the inventory of pentacyclic triterpenoids. The results indicate that hopanoid abundance is enhanced at lower salinity and higher nitrate concentration. The production of most pentacyclic triterpenoids was favored at low salinity, especially for aminotriol. Interestingly, 3-methyl-aminotetrol and tetrahymanol were favored at higher salinity. Bacteriohopanepolyols (BHPs), particularly aminotriol and 3-methyl-aminotriol, increased considerably at higher nitrate concentrations. Four novel N-containing BHPs—aminodiol, 3-methyl-aminodiol, and isomers of aminotriol and 3-methyl-aminotriol—were identified. This study highlights the significance of environmental factors for bacterial lipid production and documents the need for cultivation studies under variable conditions to utilize the full potential of the biomarker concept.
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Affiliation(s)
- Alexmar Cordova-Gonzalez
- Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany
| | - Daniel Birgel
- Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany.
| | - Andreas Kappler
- Geomikrobiologie, Zentrum für Angewandte Geowissenschaften, Universität Tübingen, Tübingen, Germany
| | - Jörn Peckmann
- Institut für Geologie, Centrum für Erdsystemforschung und Nachhaltigkeit, Universität Hamburg, Hamburg, Germany
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210
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Yadav O, Ansari M, Ansari A. Electronic structures, bonding and energetics of non-heme mono and dinuclear iron-TPA complexes: a computational exploration. Struct Chem 2021. [DOI: 10.1007/s11224-021-01775-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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211
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Wang J, Chu YX, Yao XZ, He R. Enhanced degradation of methanethiol in enrichment cultures in the presence of methane. Biochem Eng J 2021. [DOI: 10.1016/j.bej.2021.107934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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212
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Cutsail GE, Ross MO, Rosenzweig AC, DeBeer S. Towards a unified understanding of the copper sites in particulate methane monooxygenase: an X-ray absorption spectroscopic investigation. Chem Sci 2021; 12:6194-6209. [PMID: 33996018 PMCID: PMC8098663 DOI: 10.1039/d1sc00676b] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The enzymatic conversion of the greenhouse gas, methane, to a liquid fuel, methanol, is performed by methane monooxygenases (MMOs) under mild conditions. The copper stoichiometry of particulate MMO (pMMO) has been long debated, with a dicopper site previously proposed on the basis of a 2.51 Å Cu–Cu feature in extended X-ray absorption fine structure (EXAFS) data. However, recent crystallographic data and advanced electron paramagnetic resonance (EPR) characterization support the presence of only mononuclear copper sites. To reconcile these data, we have collected high-energy resolution fluorescence detected (HERFD) and partial fluorescence yield (PFY) EXAFS spectra of Methylococcus (M.) capsulatus (Bath) pMMO. Both methods reveal only monocopper sites. These data were compared to previously published pMMO PFY-EXAFS data from M. capsulatus (Bath) and Methylomicrobium alcaliphilum 20Z, supporting dicopper and monocopper sites, respectively. The FT-EXAFS feature previously attributed to a dicopper site can be reproduced by the inclusion of a metallic copper background signal. The exact position of this feature is dependent on the nature of the sample and the percentage of background contamination, indicating that visual inspection is not sufficient for identifying background metallic contributions. Additionally, an undamaged X-ray absorption spectrum was obtained, consistent with the copper oxidation-state speciation determined by EPR quantification. X-ray photodamage studies suggest that the previously observed Cu(i) XAS features are in part attributable to photodamage. This study illustrates the complex array of factors involved in EXAFS measurement and modeling of pMMO and more generally, dilute metalloproteins with multiple metal centers. Extended X-ray absorption fine structure spectroscopic analysis of particulate methane monooxygenase reveals only monocopper sites and investigates the possible origins of the previous observed dicopper signals.![]()
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Affiliation(s)
- George E Cutsail
- Max Planck Institute for Chemical Energy Conversion Stiftstrasse 34-36 D-45470 Mülheim an der Ruhr Germany .,University of Duisburg-Essen Universitätsstrasse 7 D-45151 Essen Germany
| | - Matthew O Ross
- Departments of Molecular Biosciences and Chemistry, Northwestern University Evanston 60208 IL USA
| | - Amy C Rosenzweig
- Departments of Molecular Biosciences and Chemistry, Northwestern University Evanston 60208 IL USA
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion Stiftstrasse 34-36 D-45470 Mülheim an der Ruhr Germany
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213
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Khider MLK, Brautaset T, Irla M. Methane monooxygenases: central enzymes in methanotrophy with promising biotechnological applications. World J Microbiol Biotechnol 2021; 37:72. [PMID: 33765207 PMCID: PMC7994243 DOI: 10.1007/s11274-021-03038-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 03/09/2021] [Indexed: 12/02/2022]
Abstract
Worldwide, the use of methane is limited to generating power, electricity, heating, and for production of chemicals. We believe this valuable gas can be employed more widely. Here we review the possibility of using methane as a feedstock for biotechnological processes based on the application of synthetic methanotrophs. Methane monooxygenase (MMO) enables aerobic methanotrophs to utilize methane as a sole carbon and energy source, in contrast to industrial microorganisms that grow on carbon sources, such as sugar cane, which directly compete with the food market. However, naturally occurring methanotrophs have proven to be difficult to manipulate genetically and their current industrial use is limited to generating animal feed biomass. Shifting the focus from genetic engineering of methanotrophs, towards introducing metabolic pathways for methane utilization in familiar industrial microorganisms, may lead to construction of efficient and economically feasible microbial cell factories. The applications of a technology for MMO production are not limited to methane-based industrial synthesis of fuels and value-added products, but are also of interest in bioremediation where mitigating anthropogenic pollution is an increasingly relevant issue. Published research on successful functional expression of MMO does not exist, but several attempts provide promising future perspectives and a few recent patents indicate that there is an ongoing research in this field. Combining the knowledge on genetics and metabolism of methanotrophy with tools for functional heterologous expression of MMO-encoding genes in non-methanotrophic bacterial species, is a key step for construction of synthetic methanotrophs that holds a great biotechnological potential.
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Affiliation(s)
- May L K Khider
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Trygve Brautaset
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway
| | - Marta Irla
- Department of Biotechnology and Food Science, Norwegian University of Science and Technology, Trondheim, Norway.
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214
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Carere CR, Hards K, Wigley K, Carman L, Houghton KM, Cook GM, Stott MB. Growth on Formic Acid Is Dependent on Intracellular pH Homeostasis for the Thermoacidophilic Methanotroph Methylacidiphilum sp. RTK17.1. Front Microbiol 2021; 12:651744. [PMID: 33841379 PMCID: PMC8024496 DOI: 10.3389/fmicb.2021.651744] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Accepted: 02/22/2021] [Indexed: 12/13/2022] Open
Abstract
Members of the genus Methylacidiphilum, a clade of metabolically flexible thermoacidophilic methanotrophs from the phylum Verrucomicrobia, can utilize a variety of substrates including methane, methanol, and hydrogen for growth. However, despite sequentially oxidizing methane to carbon dioxide via methanol and formate intermediates, growth on formate as the only source of reducing equivalents (i.e., NADH) has not yet been demonstrated. In many acidophiles, the inability to grow on organic acids has presumed that diffusion of the protonated form (e.g., formic acid) into the cell is accompanied by deprotonation prompting cytosolic acidification, which leads to the denaturation of vital proteins and the collapse of the proton motive force. In this work, we used a combination of biochemical, physiological, chemostat, and transcriptomic approaches to demonstrate that Methylacidiphilum sp. RTK17.1 can utilize formate as a substrate when cells are able to maintain pH homeostasis. Our findings show that Methylacidiphilum sp. RTK17.1 grows optimally with a circumneutral intracellular pH (pH 6.52 ± 0.04) across an extracellular range of pH 1.5–3.0. In batch experiments, formic acid addition resulted in no observable cell growth and cell death due to acidification of the cytosol. Nevertheless, stable growth on formic acid as the only source of energy was demonstrated in continuous chemostat cultures (D = 0.0052 h−1, td = 133 h). During growth on formic acid, biomass yields remained nearly identical to methanol-grown chemostat cultures when normalized per mole electron equivalent. Transcriptome analysis revealed the key genes associated with stress response: methane, methanol, and formate metabolism were differentially expressed in response to growth on formic acid. Collectively, these results show formic acid represents a utilizable source of energy/carbon to the acidophilic methanotrophs within geothermal environments. Findings expand the known metabolic flexibility of verrucomicrobial methanotrophs to include organic acids and provide insight into potential survival strategies used by these species during methane starvation.
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Affiliation(s)
- Carlo R Carere
- Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Kiel Hards
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Center for Molecular Biodiscovery, Auckland, New Zealand
| | - Kathryn Wigley
- Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Luke Carman
- Department of Chemical and Process Engineering, University of Canterbury, Christchurch, New Zealand
| | - Karen M Houghton
- Geomicrobiology Research Group, Department of Geothermal Sciences, GNS Science, Taupō, New Zealand
| | - Gregory M Cook
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.,Maurice Wilkins Center for Molecular Biodiscovery, Auckland, New Zealand
| | - Matthew B Stott
- School of Biological Sciences, University of Canterbury, Christchurch, New Zealand
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215
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Carrell AA, Schwartz GE, Cregger MA, Gionfriddo CM, Elias DA, Wilpiszeski RL, Klingeman DM, Wymore AM, Muller KA, Brooks SC. Nutrient Exposure Alters Microbial Composition, Structure, and Mercury Methylating Activity in Periphyton in a Contaminated Watershed. Front Microbiol 2021; 12:647861. [PMID: 33815336 PMCID: PMC8017159 DOI: 10.3389/fmicb.2021.647861] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Accepted: 02/22/2021] [Indexed: 01/04/2023] Open
Abstract
The conversion of mercury (Hg) to monomethylmercury (MMHg) is a critical area of concern in global Hg cycling. Periphyton biofilms may harbor significant amounts of MMHg but little is known about the Hg-methylating potential of the periphyton microbiome. Therefore, we used high-throughput amplicon sequencing of the 16S rRNA gene, ITS2 region, and Hg methylation gene pair (hgcAB) to characterize the archaea/bacteria, fungi, and Hg-methylating microorganisms in periphyton communities grown in a contaminated watershed in East Tennessee (United States). Furthermore, we examined how nutrient amendments (nitrate and/or phosphate) altered periphyton community structure and function. We found that bacterial/archaeal richness in experimental conditions decreased in summer and increased in autumn relative to control treatments, while fungal diversity generally increased in summer and decreased in autumn relative to control treatments. Interestingly, the Hg-methylating communities were dominated by Proteobacteria followed by Candidatus Atribacteria across both seasons. Surprisingly, Hg methylation potential correlated with numerous bacterial families that do not contain hgcAB, suggesting that the overall microbiome structure of periphyton communities influences rates of Hg transformation within these microbial mats. To further explore these complex community interactions, we performed a microbial network analysis and found that the nitrate-amended treatment resulted in the highest number of hub taxa that also corresponded with enhanced Hg methylation potential. This work provides insight into community interactions within the periphyton microbiome that may contribute to Hg cycling and will inform future research that will focus on establishing mixed microbial consortia to uncover mechanisms driving shifts in Hg cycling within periphyton habitats.
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Affiliation(s)
- Alyssa A Carrell
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Grace E Schwartz
- Oak Ridge National Laboratory, Environmental Science Division, Oak Ridge, TN, United States.,Department of Chemistry, Wofford College, Spartanburg, SC, United States
| | - Melissa A Cregger
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Caitlin M Gionfriddo
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States.,Smithsonian Environmental Research Center, Edgewater, MD, United States
| | - Dwayne A Elias
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Regina L Wilpiszeski
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Dawn M Klingeman
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Ann M Wymore
- Oak Ridge National Laboratory, Biosciences Division, Oak Ridge, TN, United States
| | - Katherine A Muller
- Pacific Northwest National Laboratory, Earth Systems Science Division, Richland, WA, United States
| | - Scott C Brooks
- Oak Ridge National Laboratory, Environmental Science Division, Oak Ridge, TN, United States
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216
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Li Q, Peng C, Zhang J, Li Y, Song X. Nitrogen addition decreases methane uptake caused by methanotroph and methanogen imbalances in a Moso bamboo forest. Sci Rep 2021; 11:5578. [PMID: 33692387 PMCID: PMC7947007 DOI: 10.1038/s41598-021-84422-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 02/11/2021] [Indexed: 11/23/2022] Open
Abstract
Forest soils play an important role in controlling global warming by reducing atmospheric methane (CH4) concentrations. However, little attention has been paid to how nitrogen (N) deposition may alter microorganism communities that are related to the CH4 cycle or CH4 oxidation in subtropical forest soils. We investigated the effects of N addition (0, 30, 60, or 90 kg N ha−1 yr−1) on soil CH4 flux and methanotroph and methanogen abundance, diversity, and community structure in a Moso bamboo (Phyllostachys edulis) forest in subtropical China. N addition significantly increased methanogen abundance but reduced both methanotroph and methanogen diversity. Methanotroph and methanogen community structures under the N deposition treatments were significantly different from those of the control. In N deposition treatments, the relative abundance of Methanoculleus was significantly lower than that in the control. Soil pH was the key factor regulating the changes in methanotroph and methanogen diversity and community structure. The CH4 emission rate increased with N addition and was negatively correlated with both methanotroph and methanogen diversity but positively correlated with methanogen abundance. Overall, our results suggested that N deposition can suppress CH4 uptake by altering methanotroph and methanogen abundance, diversity, and community structure in subtropical Moso bamboo forest soils.
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Affiliation(s)
- Quan Li
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, 712100, China.,State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Changhui Peng
- Center for Ecological Forecasting and Global Change, College of Forestry, Northwest A&F University, Yangling, 712100, China. .,Department of Biology Sciences, Institute of Environment Sciences, University of Quebec at Montreal, Case Postale 8888, Succursale Centre-Ville, Montreal, H3C3P8, Canada.
| | - Junbo Zhang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Yongfu Li
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China
| | - Xinzhang Song
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou, 311300, China.
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217
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Sahoo KK, Goswami G, Das D. Biotransformation of Methane and Carbon Dioxide Into High-Value Products by Methanotrophs: Current State of Art and Future Prospects. Front Microbiol 2021; 12:636486. [PMID: 33776968 PMCID: PMC7987672 DOI: 10.3389/fmicb.2021.636486] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 02/22/2021] [Indexed: 01/16/2023] Open
Abstract
Conventional chemical methods to transform methane and carbon dioxide into useful chemicals are plagued by the requirement for extreme operating conditions and expensive catalysts. Exploitation of microorganisms as biocatalysts is an attractive alternative to sequester these C1 compounds and convert them into value-added chemicals through their inherent metabolic pathways. Microbial biocatalysts are advantageous over chemical processes as they require mild-operating conditions and do not release any toxic by-products. Methanotrophs are potential cell-factories for synthesizing a wide range of high-value products via utilizing methane as the sole source of carbon and energy, and hence, serve as excellent candidate for methane sequestration. Besides, methanotrophs are capable of capturing carbon dioxide and enzymatically hydrogenating it into methanol, and hence qualify to be suitable candidates for carbon dioxide sequestration. However, large-scale production of value-added products from methanotrophs still presents an overwhelming challenge, due to gas-liquid mass transfer limitations, low solubility of gases in liquid medium and low titer of products. This requires design and engineering of efficient reactors for scale-up of the process. The present review offers an overview of the metabolic architecture of methanotrophs and the range of product portfolio they can offer. Special emphasis is given on methanol biosynthesis as a potential biofuel molecule, through utilization of methane and alternate pathway of carbon dioxide sequestration. In view of the gas-liquid mass transfer and low solubility of gases, the key rate-limiting step in gas fermentation, emphasis is given toward reactor design consideration essential to achieve better process performance.
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Affiliation(s)
- Krishna Kalyani Sahoo
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
| | - Gargi Goswami
- Department of Biotechnology, Gandhi Institute of Technology and Management (GITAM) University, Visakhapatnam, India
| | - Debasish Das
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, India
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218
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Abstract
Methanotrophic bacteria represent a potential route to methane utilization and mitigation of methane emissions. In the first step of their metabolic pathway, aerobic methanotrophs use methane monooxygenases (MMOs) to activate methane, oxidizing it to methanol. There are two types of MMOs: a particulate, membrane-bound enzyme (pMMO) and a soluble, cytoplasmic enzyme (sMMO). The two MMOs are completely unrelated, with different architectures, metal cofactors, and mechanisms. The more prevalent of the two, pMMO, is copper-dependent, but the identity of its copper active site remains unclear. By contrast, sMMO uses a diiron active site, the catalytic cycle of which is well understood. Here we review the current state of knowledge for both MMOs, with an emphasis on recent developments and emerging hypotheses. In addition, we discuss obstacles to developing expression systems, which are needed to address outstanding questions and to facilitate future protein engineering efforts.
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Affiliation(s)
- Christopher W Koo
- Departments of Molecular Biosciences and of Chemistry, Northwestern University, Evanston, IL 60208, USA.
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219
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Rainer EM, Seppey CVW, Tveit AT, Svenning MM. Methanotroph populations and CH4 oxidation potentials in high-Arctic peat are altered by herbivory induced vegetation change. FEMS Microbiol Ecol 2021; 96:5868763. [PMID: 32639555 PMCID: PMC8202349 DOI: 10.1093/femsec/fiaa140] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 07/07/2020] [Indexed: 01/11/2023] Open
Abstract
Methane oxidizing bacteria (methanotrophs) within the genus
Methylobacter constitute the biological filter for methane
(CH4) in many Arctic soils. Multiple Methylobacter strains
have been identified in these environments but we seldom know the ecological significance
of the different strains. High-Arctic peatlands in Svalbard are heavily influenced by
herbivory, leading to reduced vascular plant and root biomass. Here, we have measured
potential CH4 oxidation rates and identified the active methantrophs in grazed
peat and peat protected from grazing by fencing (exclosures) for 18 years. Grazed peat
sustained a higher water table, higher CH4 concentrations and lower oxygen
(O2) concentrations than exclosed peat. Correspondingly, the highest
CH4 oxidation potentials were closer to the O2 rich surface in the
grazed than in the protected peat. A comparison of 16S rRNA genes showed that the majority
of methanotrophs in both sites belong to the genus Methylobacter. Further
analyses of pmoA transcripts revealed that several
Methylobacter OTUs were active in the peat but that different OTUs
dominated the grazed peat than the exclosed peat. We conclude that grazing influences soil
conditions, the active CH4 filter and that different
Methylobacter populations are responsible for CH4 oxidation
depending on the environmental conditions.
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Affiliation(s)
- Edda M Rainer
- Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Christophe V W Seppey
- Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Alexander T Tveit
- Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Mette M Svenning
- Department of Arctic and Marine Biology, UiT - The Arctic University of Norway, Tromsø, Norway
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220
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Park YR, Kim DH, Choi KH, Kim YW, Lee EY, Park BJ. Biofuel upgrade reactions via phase-transfer catalysis of methanotrophs. J IND ENG CHEM 2021. [DOI: 10.1016/j.jiec.2021.01.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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221
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Zhou X, Smaill SJ, Gu X, Clinton PW. Manipulation of soil methane oxidation under drought stress. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 757:144089. [PMID: 33310579 DOI: 10.1016/j.scitotenv.2020.144089] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/20/2020] [Accepted: 11/22/2020] [Indexed: 06/12/2023]
Abstract
Drought events are predicted to occur more frequently, but comprehensive knowledge of their effects on methane (CH4) oxidation by soil methanotrophs in upland ecosystems remains elusive. Here, we put forward a new conceptual model in which drought influences soil CH4 oxidation through a direct pathway (i.e., positive effects of soil CH4 oxidation via increasing soil aeration) and through an indirect pathway (i.e., negative effects of in planta ethylene (C2H4) production on soil CH4 oxidation). Through measuring soil CH4 efflux along a gradient of drought stress, we found that drought increases soil CH4 oxidation, as the former outweighs the latter on soil CH4 oxidation, based on a mesocosm experiment employing distinct levels of watering and a long-term drought field trial created by rainfall exclusion in a subtropical evergreen forest. Moreover, we used aminoethoxyvinylglycine (AVG), a C2H4 biosynthesis inhibitor, to reduce in planta C2H4 production under drought, and found that reducing in planta C2H4 production increased soil CH4 oxidation under drought. To confirm these findings, we found that inoculation of plant growth-promoting rhizobacteria containing the 1-aminocyclopropane-1-carboxylate deaminase alleviated the negative effects of drought-induced in planta C2H4, thus increasing soil CH4 oxidation rates. All these results provide strong evidence for the hypothesis that in planta C2H4 production inhibits soil CH4 oxidation under drought. To our knowledge, this is the first study to manipulate the negative feedback between C2H4 production and CH4 oxidation under drought stress. Given the current widespread extent of arid and semiarid regions in the world, combined with the projected increased frequency of drought stress in future climate scenarios, we provide a reliable means for increasing soil CH4 oxidation in the context of global warming.
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Affiliation(s)
- Xiaoqi Zhou
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China.
| | - Simeon J Smaill
- Scion, P.O. Box 29237, Riccarton, Christchurch 8440, New Zealand
| | - Xinyun Gu
- Zhejiang Tiantong Forest Ecosystem National Observation and Research Station, Center for Global Change and Ecological Forecasting, School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Peter W Clinton
- Scion, P.O. Box 29237, Riccarton, Christchurch 8440, New Zealand
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222
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Microbial Communities in Methane Cycle: Modern Molecular Methods Gain Insights into Their Global Ecology. ENVIRONMENTS 2021. [DOI: 10.3390/environments8020016] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The role of methane as a greenhouse gas in the concept of global climate changes is well known. Methanogens and methanotrophs are two microbial groups which contribute to the biogeochemical methane cycle in soil, so that the total emission of CH4 is the balance between its production and oxidation by microbial communities. Traditional identification techniques, such as selective enrichment and pure-culture isolation, have been used for a long time to study diversity of methanogens and methanotrophs. However, these techniques are characterized by significant limitations, since only a relatively small fraction of the microbial community could be cultured. Modern molecular methods for quantitative analysis of the microbial community such as real-time PCR (Polymerase chain reaction), DNA fingerprints and methods based on high-throughput sequencing together with different “omics” techniques overcome the limitations imposed by culture-dependent approaches and provide new insights into the diversity and ecology of microbial communities in the methane cycle. Here, we review available knowledge concerning the abundances, composition, and activity of methanogenic and methanotrophic communities in a wide range of natural and anthropogenic environments. We suggest that incorporation of microbial data could fill the existing microbiological gaps in methane flux modeling, and significantly increase the predictive power of models for different environments.
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223
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Wallenius AJ, Dalcin Martins P, Slomp CP, Jetten MSM. Anthropogenic and Environmental Constraints on the Microbial Methane Cycle in Coastal Sediments. Front Microbiol 2021; 12:631621. [PMID: 33679659 PMCID: PMC7935538 DOI: 10.3389/fmicb.2021.631621] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Accepted: 01/29/2021] [Indexed: 12/05/2022] Open
Abstract
Large amounts of methane, a potent greenhouse gas, are produced in anoxic sediments by methanogenic archaea. Nonetheless, over 90% of the produced methane is oxidized via sulfate-dependent anaerobic oxidation of methane (S-AOM) in the sulfate-methane transition zone (SMTZ) by consortia of anaerobic methane-oxidizing archaea (ANME) and sulfate-reducing bacteria (SRB). Coastal systems account for the majority of total marine methane emissions and typically have lower sulfate concentrations, hence S-AOM is less significant. However, alternative electron acceptors such as metal oxides or nitrate could be used for AOM instead of sulfate. The availability of electron acceptors is determined by the redox zonation in the sediment, which may vary due to changes in oxygen availability and the type and rate of organic matter inputs. Additionally, eutrophication and climate change can affect the microbiome, biogeochemical zonation, and methane cycling in coastal sediments. This review summarizes the current knowledge on the processes and microorganisms involved in methane cycling in coastal sediments and the factors influencing methane emissions from these systems. In eutrophic coastal areas, organic matter inputs are a key driver of bottom water hypoxia. Global warming can reduce the solubility of oxygen in surface waters, enhancing water column stratification, increasing primary production, and favoring methanogenesis. ANME are notoriously slow growers and may not be able to effectively oxidize methane upon rapid sedimentation and shoaling of the SMTZ. In such settings, ANME-2d (Methanoperedenaceae) and ANME-2a may couple iron- and/or manganese reduction to AOM, while ANME-2d and NC10 bacteria (Methylomirabilota) could couple AOM to nitrate or nitrite reduction. Ultimately, methane may be oxidized by aerobic methanotrophs in the upper millimeters of the sediment or in the water column. The role of these processes in mitigating methane emissions from eutrophic coastal sediments, including the exact pathways and microorganisms involved, are still underexplored, and factors controlling these processes are unclear. Further studies are needed in order to understand the factors driving methane-cycling pathways and to identify the responsible microorganisms. Integration of the knowledge on microbial pathways and geochemical processes is expected to lead to more accurate predictions of methane emissions from coastal zones in the future.
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Affiliation(s)
- Anna J. Wallenius
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, Netherlands
| | - Paula Dalcin Martins
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, Netherlands
| | - Caroline P. Slomp
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Utrecht, Netherlands
| | - Mike S. M. Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, Netherlands
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224
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Mass spectrometry-based approaches to study lanthanides and lanthanide-dependent proteins in the phyllosphere. Methods Enzymol 2021; 650:215-236. [PMID: 33867023 DOI: 10.1016/bs.mie.2021.01.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Rare-earth elements (REEs) were recently discovered to be biologically significant. The finding was originally made with the methanol dehydrogenase XoxF, which depends on REEs for its activity, and reports of lanthanide-utilizing bacteria have since expanded. Environmental proteomics allows the identification of proteins specifically induced by the presence of lanthanides or can provide insights into the preferred use of lanthanide-dependent and -independent isoenzymes, for example. Here we describe protocols for the growth and subsequent mass spectrometry-based proteome analysis of bacteria obtained from controlled artificial media and from the phyllosphere of the model plant Arabidopsis thaliana. In addition, the use of inductively coupled plasma mass spectrometry (ICP-MS) is described for the quantification of REEs in biological samples.
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225
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Hogendoorn C, Picone N, van Hout F, Vijverberg S, Poghosyan L, van Alen TA, Frank J, Pol A, Gagliano AL, Jetten MSM, D'Alessandro W, Quatrini P, Op den Camp HJM. Draft genome of a novel methanotrophic Methylobacter sp. from the volcanic soils of Pantelleria Island. Antonie van Leeuwenhoek 2021; 114:313-324. [PMID: 33566237 PMCID: PMC7902576 DOI: 10.1007/s10482-021-01525-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 01/22/2021] [Indexed: 11/27/2022]
Abstract
The genus Methylobacter is considered an important and often dominant group of aerobic methane-oxidizing bacteria in many oxic ecosystems, where members of this genus contribute to the reduction of CH4 emissions. Metagenomic studies of the upper oxic layers of geothermal soils of the Favara Grande, Pantelleria, Italy, revealed the presence of various methane-oxidizing bacteria, and resulted in a near complete metagenome assembled genome (MAG) of an aerobic methanotroph, which was classified as a Methylobacter species. In this study, the Methylobacter sp. B2 MAG was used to investigate its metabolic potential and phylogenetic affiliation. The MAG has a size of 4,086,539 bp, consists of 134 contigs and 3955 genes were found, of which 3902 were protein coding genes. All genes for CH4 oxidation to CO2 were detected, including pmoCAB encoding particulate methane monooxygenase (pMMO) and xoxF encoding a methanol dehydrogenase. No gene encoding a formaldehyde dehydrogenase was present and the formaldehyde to formate conversion follows the tetrahydromethanopterin (H4MPT) pathway. “Ca. Methylobacter favarea” B2 uses the Ribulose-Mono-Phosphate (RuMP) pathway for carbon fixation. Analysis of the MAG indicates that Na+/H+ antiporters and the urease system might be important in the maintenance of pH homeostasis of this strain to cope with acidic conditions. So far, thermoacidophilic Methylobacter species have not been isolated, however this study indicates that members of the genus Methylobacter can be found in distinct ecosystems and their presence is not restricted to freshwater or marine sediments.
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Affiliation(s)
- Carmen Hogendoorn
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Femke van Hout
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Sophie Vijverberg
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Lianna Poghosyan
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Theo A van Alen
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Jeroen Frank
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Antonia L Gagliano
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palerma, Via U. La Malfa 153, 90146, Palermo, Italy
| | - Mike S M Jetten
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Walter D'Alessandro
- Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Palerma, Via U. La Malfa 153, 90146, Palermo, Italy
| | - Paola Quatrini
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Ed. 16, 90128, Palermo, Italy
| | - Huub J M Op den Camp
- Department of Microbiology, IWWR, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands.
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226
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Razzaghy-Azar M, Nourbakhsh M, Vafadar M, Nourbakhsh M, Talebi S, Sharifi-Zarchi A, Salehi Siavashani E, Garshasbi M. A novel metabolic disorder in the degradation pathway of endogenous methanol due to a mutation in the gene of alcohol dehydrogenase. Clin Biochem 2021; 90:66-72. [PMID: 33539811 DOI: 10.1016/j.clinbiochem.2021.01.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 01/16/2021] [Accepted: 01/19/2021] [Indexed: 11/26/2022]
Abstract
BACKGROUND A small amount of methanol is produced endogenously in the human body but it is efficiently metabolized by alcohol dehydrogenase (ADH) and other enzymes, and the products eliminated without harm. In this study, we present a new entity of inborn error of methanol metabolism due to a mutation in the ADH1C gene coding for the γ subunit that is part of several ADH isoenzymes. RESULTS This disorder was discovered in an 11.58-year-old boy. During one 9-month hospital admission, he had periods of 1-4 days during which he was comatose, and between these periods he was sometimes verbose and euphoric, and had ataxia, dysarthria. Following hemodialysis treatments, he became conscious and appeared healthy. Organ evaluations and his laboratory tests were normal. Toxicological evaluation of his blood showed a high methanol level [12.2 mg/dL (3.8 mmol/L), normal range up to 3.5 mg/dL (1.09 mmol/L) while the formaldehyde level was undetectable. The finding of liver function tests that were within normal limits, coupled with a normal eye examination and size of the liver, elevated blood methanol levels and an undetectable formaldehyde level, suggested ADH insufficiency. Adding zinc to the drug regimen 15 mg/daily dramatically reduced the patient's methanol level and alleviated the abnormal symptoms. When zinc supplementation was discontinued, the patient relapsed into a coma and hemodialysis was once again required. A homozygous mutation in ADH1C gene located at exon 3 was found, and both parents were heterozygous for this mutation. CONCLUSION Accumulation of methanol due to mutation in ADH1C gene may result in drunkenness and ataxia, and leads to coma. This condition can be successfully treated with zinc supplementation as the cofactor of ADH.
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Affiliation(s)
- Maryam Razzaghy-Azar
- Hazrat Aliasghar Children's Hospital, Iran University of Medical Sciences, Tehran, Iran; Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mitra Nourbakhsh
- Department of Biochemistry, School of Medicine, Iran University of Medical Sciences, Tehran, Iran; Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Mehdi Vafadar
- Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Mona Nourbakhsh
- Metabolic Disorders Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Saeed Talebi
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Ali Sharifi-Zarchi
- Computer Engineering Department, Sharif University of Technology, Tehran, Iran
| | | | - Masoud Garshasbi
- Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
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227
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Schmitz RA, Peeters SH, Versantvoort W, Picone N, Pol A, Jetten MSM, Op den Camp HJM. Verrucomicrobial methanotrophs: ecophysiology of metabolically versatile acidophiles. FEMS Microbiol Rev 2021; 45:6125968. [PMID: 33524112 PMCID: PMC8498564 DOI: 10.1093/femsre/fuab007] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Methanotrophs are an important group of microorganisms that counteract methane emissions to the atmosphere. Methane-oxidising bacteria of the Alpha- and Gammaproteobacteria have been studied for over a century, while methanotrophs of the phylum Verrucomicrobia are a more recent discovery. Verrucomicrobial methanotrophs are extremophiles that live in very acidic geothermal ecosystems. Currently, more than a dozen strains have been isolated, belonging to the genera Methylacidiphilum and Methylacidimicrobium. Initially, these methanotrophs were thought to be metabolically confined. However, genomic analyses and physiological and biochemical experiments over the past years revealed that verrucomicrobial methanotrophs, as well as proteobacterial methanotrophs, are much more metabolically versatile than previously assumed. Several inorganic gases and other molecules present in acidic geothermal ecosystems can be utilised, such as methane, hydrogen gas, carbon dioxide, ammonium, nitrogen gas and perhaps also hydrogen sulfide. Verrucomicrobial methanotrophs could therefore represent key players in multiple volcanic nutrient cycles and in the mitigation of greenhouse gas emissions from geothermal ecosystems. Here, we summarise the current knowledge on verrucomicrobial methanotrophs with respect to their metabolic versatility and discuss the factors that determine their diversity in their natural environment. In addition, key metabolic, morphological and ecological characteristics of verrucomicrobial and proteobacterial methanotrophs are reviewed.
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Affiliation(s)
- Rob A Schmitz
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Stijn H Peeters
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Wouter Versantvoort
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Nunzia Picone
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Arjan Pol
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Mike S M Jetten
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
| | - Huub J M Op den Camp
- Department of Microbiology, Institute for Water and Wetland Research, Radboud University, Heyendaalseweg 135, 6525 AJ, Nijmegen, The Netherlands
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228
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Jawaharraj K, Sudha Dhiman S, Bedwell S, Vemuri B, Islam J, Sani RK, Gadhamshetty V. Electricity from methane by Methylococcus capsulatus (Bath) and Methylosinus trichosporium OB3b. BIORESOURCE TECHNOLOGY 2021; 321:124398. [PMID: 33257167 DOI: 10.1016/j.biortech.2020.124398] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 10/31/2020] [Accepted: 11/06/2020] [Indexed: 06/12/2023]
Abstract
Given the difficulties valorizing methane (CH4) via catalytic routes, this study explores use of CH4-oxidizing bacteria ("methanotrophs") for generating electricity directly from CH4. A preconditioned methanotrophic biofilm on 3D nickel foam with reduced graphene oxide (rGO/Ni) was used as the anode in two-compartment microbial fuel cells (MFCs). This study demonstrates a proof of concept for turning CH4 into electricity by two model methanotrophs including Methylosinus trichosposium OB3b and Methylococcus capsulatus (Bath). Both OB3b (205 mW.m-2) and Bath (110 mW.m-2) strains yielded a higher electricity from CH4 when grown on rGO/Ni compared to graphite felt electrodes. Based on electrochemistry tests, molecular dynamics simulations, genome annotations and interaction analysis, a mechanistic understanding of reasons behind enhanced performance of methanotrophs grown on rGO/Ni are presented.
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Affiliation(s)
- Kalimuthu Jawaharraj
- Department of Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD 57701, USA
| | - Saurabh Sudha Dhiman
- BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; Chemical and Biological Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD 57701, USA
| | - Sierra Bedwell
- Department of Microbiology and Immunology, Montana State University, Culbertson Hall, 100, Bozeman, MT 59717, USA
| | - Bhuvan Vemuri
- Department of Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA
| | - Jamil Islam
- Department of Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA
| | - Rajesh Kumar Sani
- BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; Chemical and Biological Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD 57701, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD 57701, USA
| | - Venkataramana Gadhamshetty
- Department of Civil and Environmental Engineering, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; BuG ReMeDEE Consortia, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD, USA; 2D-materials for Biofilm Engineering, Science and Technology (2DBEST) Center, South Dakota Mines, 501 E. St. Joseph Street, Rapid City, SD 57701, USA.
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Rissanen AJ, Saarela T, Jäntti H, Buck M, Peura S, Aalto SL, Ojala A, Pumpanen J, Tiirola M, Elvert M, Nykänen H. Vertical stratification patterns of methanotrophs and their genetic controllers in water columns of oxygen-stratified boreal lakes. FEMS Microbiol Ecol 2021; 97:fiaa252. [PMID: 33316049 PMCID: PMC7840105 DOI: 10.1093/femsec/fiaa252] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Accepted: 12/10/2020] [Indexed: 11/20/2022] Open
Abstract
The vertical structuring of methanotrophic communities and its genetic controllers remain understudied in the water columns of oxygen-stratified lakes. Therefore, we used 16S rRNA gene sequencing to study the vertical stratification patterns of methanotrophs in two boreal lakes, Lake Kuivajärvi and Lake Lovojärvi. Furthermore, metagenomic analyses were performed to assess the genomic characteristics of methanotrophs in Lovojärvi and the previously studied Lake Alinen Mustajärvi. The methanotroph communities were vertically structured along the oxygen gradient. Alphaproteobacterial methanotrophs preferred oxic water layers, while Methylococcales methanotrophs, consisting of putative novel genera and species, thrived, especially at and below the oxic-anoxic interface and showed distinct depth variation patterns, which were not completely predictable by their taxonomic classification. Instead, genomic differences among Methylococcales methanotrophs explained their variable vertical depth patterns. Genes in clusters of orthologous groups (COG) categories L (replication, recombination and repair) and S (function unknown) were relatively high in metagenome-assembled genomes representing Methylococcales clearly thriving below the oxic-anoxic interface, suggesting genetic adaptations for increased stress tolerance enabling living in the hypoxic/anoxic conditions. By contrast, genes in COG category N (cell motility) were relatively high in metagenome-assembled genomes of Methylococcales thriving at the oxic-anoxic interface, which suggests genetic adaptations for increased motility at the vertically fluctuating oxic-anoxic interface.
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Affiliation(s)
- Antti J Rissanen
- Faculty of Engineering and Natural Sciences, Tampere University, Korkeakoulunkatu 6, FI-33720, Tampere, Finland
| | - Taija Saarela
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Helena Jäntti
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Moritz Buck
- Department of Ecology and Genetics/Limnology, Uppsala University, Norbyvägen 18D, SE-75236, Uppsala, Sweden
- Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, box 7050, SE-75007, Uppsala, Sweden
| | - Sari Peura
- Department of Forest Mycology and Plant Pathology, Science for Life Laboratory, Swedish University of Agricultural Sciences, Almas allé 5, SE-75651, Uppsala, Sweden
| | - Sanni L Aalto
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, FI-40014, Jyväskylä, Finland
| | - Anne Ojala
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 1, FI-00014, Helsinki, Finland
- Institute of Atmospheric and Earth System Research (INAR)/Forest Sciences, Faculty of Agriculture and Forestry, University of Helsinki, Viikinkaari 1, FI-00014, Helsinki, Finland
| | - Jukka Pumpanen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
| | - Marja Tiirola
- Department of Biological and Environmental Sciences, University of Jyväskylä, Survontie 9 C, FI-40014, Jyväskylä, Finland
| | - Marcus Elvert
- MARUM - Center for Marine Environmental Sciences & Faculty of Geosciences, University of Bremen, Leobener Str. 8, D-28359, Bremen, Germany
| | - Hannu Nykänen
- Department of Environmental and Biological Sciences, University of Eastern Finland, Yliopistonranta 1 E, FI-70210, Kuopio, Finland
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Xie H, Chen J, Feng L, He L, Zhou C, Hong P, Sun S, Zhao H, Liang Y, Ren L, Zhang Y, Li C. Chemotaxis-selective colonization of mangrove rhizosphere microbes on nine different microplastics. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 752:142223. [PMID: 33207502 DOI: 10.1016/j.scitotenv.2020.142223] [Citation(s) in RCA: 65] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 05/26/2023]
Abstract
Microplastics pollution poses a new threat to the environment of intertidal zone. The sea forest, mangrove, has been polluted by a large number of plastic debris worldwide. To fill the gaps in knowledge of mangrove rhizosphere microbes connected with the 'plasticsphere', a semi-controlled in situ exposure experiment for nine different types of microplastics were conducted in mangrove ecosystem. A sign of biodegrading was observed on polyethylene, polyamide 6 and polyvinyl chloride microplastics surface after 3 months exposure. We discovered that the metabolic activities of the dominant bacteria on certain microplastics were related to the specific groups on polymers molecule. The selective colonization may be driven by the chemotaxis of bacteria. Specially, microplastics biofilms of polyethylene, polyamide 6, polyvinyl chloride and expanded polystyrene possess distinctive dominant bacteria assemblages which have great significance in ecosystem processes involving carbon cycle or sulfur cycle. Community of mangrove soil microorganism and microplastic biofilm varies as the seasons changes. As a new niche, microplastics has higher inclusivity to bacteria than surrounding soil. Additionally, pathogens for human beings (Vibrio parahaemolyticus and Escherichia-Shigella) were detected both in microplastics and soil. We stress that the interaction between microplastics and rhizosphere microorganisms may affect the growth and health of mangrove plants. Besides, we point out that mangrove rhizosphere microorganism can be an ideal candidate for plastics-degradation.
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Affiliation(s)
- Huifeng Xie
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Jinjun Chen
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Limin Feng
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Lei He
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Chunxia Zhou
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China; Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, PR China
| | - Pengzhi Hong
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China; Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, PR China
| | - Shengli Sun
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Hui Zhao
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Yanqiu Liang
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Lei Ren
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Yueqin Zhang
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China
| | - Chengyong Li
- School of Chemistry and Environment, School of Food Science and Technology, College of Coastal Agricultural Sciences, Guangdong Ocean University, Southern Marine Science and Engineering Guangdong Laboratory, Zhanjiang 524088, PR China; Shenzhen Institute of Guangdong Ocean University, Shenzhen 518120, PR China.
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231
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DeCastro ME, Doane MP, Dinsdale EA, Rodríguez-Belmonte E, González-Siso MI. Exploring the taxonomical and functional profile of As Burgas hot spring focusing on thermostable β-galactosidases. Sci Rep 2021; 11:101. [PMID: 33420292 PMCID: PMC7794327 DOI: 10.1038/s41598-020-80489-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Accepted: 12/17/2020] [Indexed: 01/29/2023] Open
Abstract
In the present study we investigate the microbial community inhabiting As Burgas geothermal spring, located in Ourense (Galicia, Spain). The approximately 23 Gbp of Illumina sequences generated for each replicate revealed a complex microbial community dominated by Bacteria in which Proteobacteria and Aquificae were the two prevalent phyla. An association between the two most prevalent genera, Thermus and Hydrogenobacter, was suggested by the relationship of their metabolism. The high relative abundance of sequences involved in the Calvin-Benson cycle and the reductive TCA cycle unveils the dominance of an autotrophic population. Important pathways from the nitrogen and sulfur cycle are potentially taking place in As Burgas hot spring. In the assembled reads, two complete ORFs matching GH2 beta-galactosidases were found. To assess their functional characterization, the two ORFs were cloned and overexpressed in E. coli. The pTsbg enzyme had activity towards o-Nitrophenyl-β-D-galactopyranoside (ONPG) and p-Nitrophenyl-β-D-fucopyranoside, with high thermal stability and showing maximal activity at 85 °C and pH 6, nevertheless the enzyme failed to hydrolyze lactose. The other enzyme, Tsbg, was unable to hydrolyze even ONPG or lactose. This finding highlights the challenge of finding novel active enzymes based only on their sequence.
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Affiliation(s)
- María-Eugenia DeCastro
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, Universidade da Coruña, A Coruña, Spain
| | - Michael P Doane
- Department of Biology, San Diego State University, 5500 Campanile Dr., San Diego, CA, 92182, USA
- Syndey Institute of Marine Science, 19 Chowder Bay Rd, Mosman, NSW, 2088, Australia
| | - Elizabeth Ann Dinsdale
- Department of Biology, San Diego State University, 5500 Campanile Dr., San Diego, CA, 92182, USA
- College of Science and Engineering, Flinders University, Sturt Rd, Bedford Park, SA, 5042, Australia
| | - Esther Rodríguez-Belmonte
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, Universidade da Coruña, A Coruña, Spain
| | - María-Isabel González-Siso
- Grupo EXPRELA, Centro de Investigacións Científicas Avanzadas (CICA), Facultade de Ciencias, Universidade da Coruña, A Coruña, Spain.
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232
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Rumah BL, Stead CE, Claxton Stevens BH, Minton NP, Grosse-Honebrink A, Zhang Y. Isolation and characterisation of Methylocystis spp. for poly-3-hydroxybutyrate production using waste methane feedstocks. AMB Express 2021; 11:6. [PMID: 33409745 PMCID: PMC7788130 DOI: 10.1186/s13568-020-01159-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 12/07/2020] [Indexed: 11/10/2022] Open
Abstract
Waste plastic and methane emissions are two anthropogenic by-products exacerbating environmental pollution. Methane-oxidizing bacteria (methanotrophs) hold the key to solving these problems simultaneously by utilising otherwise wasted methane gas as carbon source and accumulating the carbon as poly-3-hydroxybutyrate, a biodegradable plastic polymer. Here we present the isolation and characterisation of two novel Methylocystis strains with the ability to produce up to 55.7 ± 1.9% poly-3-hydroxybutyrate of cell dry weight when grown on methane from different waste sources such as landfill and anaerobic digester gas. Methylocystis rosea BRCS1 isolated from a recreational lake and Methylocystis parvus BRCS2 isolated from a bog were whole genome sequenced using PacBio and Illumina genome sequencing technologies. In addition to potassium nitrate, these strains were also shown to grow on ammonium chloride, glutamine and ornithine as nitrogen source. Growth of Methylocystis parvus BRCS2 on Nitrate Mineral Salt (NMS) media with 0.1% methanol vapor as carbon source was demonstrated. The genetic tractability by conjugation was also determined with conjugation efficiencies up to 2.8 × 10–2 and 1.8 × 10–2 for Methylocystis rosea BRCS1 and Methylocystis parvus BRCS2 respectively using a plasmid with ColE1 origin of replication. Finally, we show that Methylocystis species can produce considerable amounts of poly-3-hydroxybutyrate on waste methane sources without impaired growth, a proof of concept which opens doors to their use in integrated bio-facilities like landfills and anaerobic digesters.
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233
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Detoxification, Active Uptake, and Intracellular Accumulation of Chromium Species by a Methane-Oxidizing Bacterium. Appl Environ Microbiol 2021; 87:AEM.00947-20. [PMID: 33127813 PMCID: PMC7783347 DOI: 10.1128/aem.00947-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 10/20/2020] [Indexed: 01/28/2023] Open
Abstract
M. capsulatus Bath is a well-characterized aerobic methane-oxidizing bacterium that has become a model system for biotechnological development of methanotrophs to perform useful reactions for environmental cleanup and for making valuable chemicals and biological products using methane gas. Interest in such technology has increased recently owing to increasing availability of low-cost methane from fossil and biological sources. Here, it is demonstrated that this versatile methanotroph can reduce the toxic contaminating heavy metal chromium(VI) to the less toxic form chromium(III) while accumulating the chromium(III) within the cells. This is expected to diminish the bioavailability of the chromium and make it less likely to be reoxidized to chromium(VI). Thus, M. capsulatus has the capacity to perform methane-driven remediation of chromium-contaminated water and other materials and to accumulate the chromium in the low-toxicity chromium(III) form within the cells. Despite the wide-ranging proscription of hexavalent chromium, chromium(VI) remains among the major polluting heavy metals worldwide. Aerobic methane-oxidizing bacteria are widespread environmental microorganisms that can perform diverse reactions using methane as the feedstock. The methanotroph Methylococcus capsulatus Bath, like many other microorganisms, detoxifies chromium(VI) by reduction to chromium(III). Here, the interaction of chromium species with M. capsulatus Bath was examined in detail by using a range of techniques. Cell fractionation and high-performance liquid chromatography–inductively coupled plasma mass spectrometry (HPLC–ICP-MS) indicated that externally provided chromium(VI) underwent reduction and was then taken up into the cytoplasmic and membranous fractions of the cells. This was confirmed by X-ray photoelectron spectroscopy (XPS) of intact cultures that indicated negligible chromium on the surfaces of or outside the cells. Distribution of chromium and other elements within intact and sectioned cells, as observed via transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDX) and electron energy loss spectroscopy (EELS), was consistent with the cytoplasm/membrane location of the chromium(III), possibly as chromium phosphate. The cells could also take up chromium(III) directly from the medium in a metabolism-dependent fashion and accumulate it. These results indicate a novel pattern of interaction with chromium species distinct from that observed previously with other microorganisms. They also suggest that M. capsulatus and similar methanotrophs may contribute directly to chromium(VI) reduction and accumulation in mixed communities of microorganisms that are able to perform methane-driven remediation of chromium(VI). IMPORTANCEM. capsulatus Bath is a well-characterized aerobic methane-oxidizing bacterium that has become a model system for biotechnological development of methanotrophs to perform useful reactions for environmental cleanup and for making valuable chemicals and biological products using methane gas. Interest in such technology has increased recently owing to increasing availability of low-cost methane from fossil and biological sources. Here, it is demonstrated that this versatile methanotroph can reduce the toxic contaminating heavy metal chromium(VI) to the less toxic form chromium(III) while accumulating the chromium(III) within the cells. This is expected to diminish the bioavailability of the chromium and make it less likely to be reoxidized to chromium(VI). Thus, M. capsulatus has the capacity to perform methane-driven remediation of chromium-contaminated water and other materials and to accumulate the chromium in the low-toxicity chromium(III) form within the cells.
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235
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Jeong HS, Hong S, Yoo HS, Kim J, Kim Y, Yoon C, Lee SJ, Kim SH. EPR-derived structures of flavin radical and iron-sulfur clusters from Methylosinus sporium 5 reductase. Inorg Chem Front 2021. [DOI: 10.1039/d0qi01334j] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electronic structures of two cofactors, the FAD radical and [2Fe–2S]+ of reduced MMOR from Methylosinus sporium strain 5 were investigated by advanced EPR spectroscopy. The findings provide long overdue detailed structural information of MMOR.
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Affiliation(s)
- Han Sol Jeong
- Western Seoul Center
- Korea Basic Science Institute (KBSI)
- Seoul 03759
- Rep. of Korea
- Department of Chemistry and Nano Science
| | - Sugyeong Hong
- Western Seoul Center
- Korea Basic Science Institute (KBSI)
- Seoul 03759
- Rep. of Korea
- Department of Chemistry and Nano Science
| | - Hee Seon Yoo
- Department of Chemistry and Institute of Molecular Biology and Genetics
- Jeonbuk National University
- Jeonju 54896
- Rep. of Korea
| | - Jin Kim
- Department of Chemistry
- Sunchon National University
- Suncheon 57922
- Rep. of Korea
| | - Yujeong Kim
- Western Seoul Center
- Korea Basic Science Institute (KBSI)
- Seoul 03759
- Rep. of Korea
- Department of Chemistry and Nano Science
| | - Chungwoon Yoon
- Department of Chemistry and Institute of Molecular Biology and Genetics
- Jeonbuk National University
- Jeonju 54896
- Rep. of Korea
| | - Seung Jae Lee
- Department of Chemistry and Institute of Molecular Biology and Genetics
- Jeonbuk National University
- Jeonju 54896
- Rep. of Korea
| | - Sun Hee Kim
- Western Seoul Center
- Korea Basic Science Institute (KBSI)
- Seoul 03759
- Rep. of Korea
- Department of Chemistry and Nano Science
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236
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Belova SE, Danilova OV, Ivanova AA, Merkel AY, Dedysh SN. Methane-Oxidizing Communities in Lichen-Dominated Forested Tundra Are Composed Exclusively of High-Affinity USCα Methanotrophs. Microorganisms 2020; 8:microorganisms8122047. [PMID: 33371270 PMCID: PMC7766663 DOI: 10.3390/microorganisms8122047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 01/04/2023] Open
Abstract
Upland soils of tundra function as a constant sink for atmospheric CH4 but the identity of methane oxidizers in these soils remains poorly understood. Methane uptake rates of -0.4 to -0.6 mg CH4-C m-2 day-1 were determined by the static chamber method in a mildly acidic upland soil of the lichen-dominated forested tundra, North Siberia, Russia. The maximal CH4 oxidation activity was localized in an organic surface soil layer underlying the lichen cover. Molecular identification of methanotrophic bacteria based on retrieval of the pmoA gene revealed Upland Soil Cluster Alpha (USCα) as the only detectable methanotroph group. Quantification of these pmoA gene fragments by means of specific qPCR assay detected ~107pmoA gene copies g-1 dry soil. The pmoA diversity was represented by seven closely related phylotypes; the most abundant phylotype displayed 97.5% identity to pmoA of Candidatus Methyloaffinis lahnbergensis. Further analysis of prokaryote diversity in this soil did not reveal 16S rRNA gene fragments from well-studied methanotrophs of the order Methylococcales and the family Methylocystaceae. The largest group of reads (~4% of all bacterial 16S rRNA gene fragments) that could potentially belong to methanotrophs was classified as uncultivated Beijerinckiaceae bacteria. These reads displayed 96-100 and 95-98% sequence similarity to 16S rRNA gene of Candidatus Methyloaffinis lahnbergensis and "Methylocapsa gorgona" MG08, respectively, and were represented by eight species-level operational taxonomic units (OTUs), two of which were highly abundant. These identification results characterize subarctic upland soils, which are exposed to atmospheric methane concentrations only, as a unique habitat colonized mostly by USCα methanotrophs.
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237
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Li C, Quan Q, Gan Y, Dong J, Fang J, Wang L, Liu J. Effects of heavy metals on microbial communities in sediments and establishment of bioindicators based on microbial taxa and function for environmental monitoring and management. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 749:141555. [PMID: 32841857 DOI: 10.1016/j.scitotenv.2020.141555] [Citation(s) in RCA: 123] [Impact Index Per Article: 30.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/19/2020] [Accepted: 08/05/2020] [Indexed: 05/20/2023]
Abstract
Heavy metals have always been a research hotspot due to their persistence, hazard and bioaccumulation. Microorganisms are highly sensitive to heavy metal pollution and play an important role in the material cycling and energy flow of the ecosystem. In order to further explore the influence of heavy metals on the diversity, composition, and function of microbial communities in the wetland sediment ecosystem, and to find suitable indicators to reflect heavy metal pollution status, we collected sediments from Huangjinxia nature reserve and determined the physicochemical properties, heavy metal (Cu, Cr, Ni, Pb, Zn, and Mn) concentrations, and microbial information. We found that: the contamination status of the study area stood at a moderate level evaluated by the pollution load index (PLI); heavy metals explained more of microbial community variation than the sediment physicochemical properties; in particular, Cr and Mn negatively affected microbial α-diversity; heavy metals significantly affected the structure of microbial communities, elements Cr, Pb, and Zn showed uniformly negative associations with the relative abundance of bacteria Nitrospirae (including class Nitrospira and order Nitrospirales), Bacteroidetes (including class Bacteroidia), and Verrucomicrobia; moreover, heavy metals affected predicted functions of microbial communities, including metabolic functions, genetic information processes, and functions related to the carbon cycle and the nitrogen cycle. Based on the relative abundance of sensitive microbial taxa and predicted functions, bioindicators [Bacteroidia], 1/[Nitrospira], 1/[Nitrification], and 1/[Aerobic nitrite oxidation] were established to reflect and predict the contamination status of heavy metals in sediments. Our in-depth research on the effects of heavy metals on microorganisms and the establishment of bioindicators provide references and new perspectives for environmental monitoring and management.
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Affiliation(s)
- Changchao Li
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Quan Quan
- State Key Laboratory of Eco-hydraulics in Northwest Arid Region of China, Xi'an University of Technology, Xi'an 710048, China.
| | - Yandong Gan
- School of Life Sciences, Qufu Normal University, Qufu 273165, China
| | - Junyu Dong
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jiaohui Fang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Lifei Wang
- Environment Research Institute, Shandong University, Qingdao 266237, China
| | - Jian Liu
- Environment Research Institute, Shandong University, Qingdao 266237, China.
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238
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Comparative Gut Microbiome Differences between Ferric Citrate and Calcium Carbonate Phosphate Binders in Patients with End-Stage Kidney Disease. Microorganisms 2020; 8:microorganisms8122040. [PMID: 33419265 PMCID: PMC7767080 DOI: 10.3390/microorganisms8122040] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 01/07/2023] Open
Abstract
Gut dysbiosis in patients with chronic kidney disease (CKD) may induce chronic inflammation and increase morbidity. Phosphate-binding agents, generally used in patients with CKD, may potentially change the composition of the gut microbiota. This study aimed to compare the microbiota composition in hemodialysis patients treated with ferric citrate or calcium carbonate. The stool microbiota was investigated in hemodialysis patients treated with ferric citrate (n = 8) and calcium carbonate (n = 46) using 16S rRNA gene amplicon sequencing profiling using linear discriminant analysis of effect size. Further predictive functional profiling of microbial communities was obtained with Tax4Fun in R. Hemodialysis patients treated with calcium carbonate had a significantly reduced microbial species diversity (Shannon index and Simpson index) and an increased microbial alteration ratio compared with patients treated with ferric citrate. A distinct microbial community structure was found in patients treated with ferric citrate, with an increased abundance of the Bacteroidetes phylum and a decreased abundance of the phylum Firmicutes. Members of the order Lactobacillales were enriched in patients treated with calcium carbonate, whereas taxa of the genera Ruminococcaceae UCG-004, Flavonifractor, and Cronobacter were enriched in patients treated with ferric citrate phosphate binder. In conclusion, Ferric citrate therapy results in a more diverse microbiome community compared to calcium carbonate therapy in hemodialysis patients with phosphate binder treatment. The gut microbiome reflects the phosphate binder choice in hemodialysis patients, further affecting the physiological environment in the gastrointestinal tract.
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239
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Praeg N, Illmer P. Microbial community composition in the rhizosphere of Larix decidua under different light regimes with additional focus on methane cycling microorganisms. Sci Rep 2020; 10:22324. [PMID: 33339837 PMCID: PMC7749151 DOI: 10.1038/s41598-020-79143-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 12/01/2020] [Indexed: 02/05/2023] Open
Abstract
Microbial community and diversity in the rhizosphere is strongly influenced by biotic and/or abiotic factors, like root exudates, nutrient availability, edaphon and climate. Here we report on the microbial diversity within the rhizosphere of Larix decidua, a dominant tree species in the Alps, as compared with the microbiome within the surrounding soil. We describe how increased light intensity influenced the rhizobiome and put emphasize on methane cycling microorganisms. Microbial taxa were classified into 26 bacterial, 4 archaeal and 6 fungal phyla revealing significant differences between bulk and rhizosphere soils. The dominant prokaryotic phyla were Proteobacteria, Acidobacteria, Actinobacteria (both, rhizosphere and bulk soil) and Bacteroidetes (rhizosphere soil only) and dominant fungal phyla in both fractions included Ascomycota and Basidiomycota. The rhizosphere community was indicated by Suillus sp., plant growth-promoting bacteria and Candidatus Saccharibacteria. Predicted genes in membrane transport and carbohydrate metabolism were significantly more abundant in rhizosphere soils while genes connected with energy metabolisms and cell motility increased in bulk soils. Dominant methanotrophic microorganisms were Upland Soil Cluster (USC) α methanotrophs, Methylogaea spp. and Methylosinus spp., while most methanogens belonged to Methanomassiliicoccales. The overall abundance of methanotrophs distinctly increased in the rhizosphere but to a very different species-specific extent. The increased light intensity only led to minor changes in the rhizobiome, nevertheless a couple of indicator species (e.g. Pseudomonas sp.) for intensified light conditions were established.
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Affiliation(s)
- Nadine Praeg
- Department of Microbiology, Universität Innsbruck, Technikerstrasse 25d, 6020, Innsbruck, Austria.
| | - Paul Illmer
- Department of Microbiology, Universität Innsbruck, Technikerstrasse 25d, 6020, Innsbruck, Austria
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240
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Jawaharraj K, Shrestha N, Chilkoor G, Dhiman SS, Islam J, Gadhamshetty V. Valorization of methane from environmental engineering applications: A critical review. WATER RESEARCH 2020; 187:116400. [PMID: 32979578 DOI: 10.1016/j.watres.2020.116400] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/29/2020] [Accepted: 09/05/2020] [Indexed: 05/09/2023]
Abstract
Wastewater and waste management sectors alone account for 18% of the anthropogenic methane (CH4) emissions. This study presents a critical overview of methanotrophs ("methane oxidizing microorganisms") for valorizing typically discarded CH4 from environmental engineering applications, focusing on wastewater treatment plants. Methanotrophs can convert CH4 into valuable bioproducts including chemicals, biodiesel, DC electricity, polymers, and S-layers, all under ambient conditions. As discarded CH4 and its oxidation products can also be used as a carbon source in nitrification and annamox processes. Here we discuss modes of CH4 assimilation by methanotrophs in both natural and engineered systems. We also highlight the technical challenges and technological breakthroughs needed to enable targeted CH4 oxidation in wastewater treatment plants.
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Affiliation(s)
- Kalimuthu Jawaharraj
- Civil and Environmental Engineering, South Dakota Mines, Rapid City 57701, SD, United States; BuG ReMeDEE consortium, South Dakota Mines, Rapid City 57701, SD, United States
| | - Namita Shrestha
- Civil and Environmental Engineering, Rose-Hulman Institute of Technology, Terre Haute 47803, IN, United States
| | - Govinda Chilkoor
- Civil and Environmental Engineering, South Dakota Mines, Rapid City 57701, SD, United States; 2-Dimensional Materials for Biofilm Engineering Science and Technology (2DBEST) Center, South Dakota School of Mines and Technology, Rapid City 57701, SD, United States
| | - Saurabh Sudha Dhiman
- BuG ReMeDEE consortium, South Dakota Mines, Rapid City 57701, SD, United States; Biological and Chemical Engineering, South Dakota School of Mines & Technology, Rapid City 57701, SD, United States
| | - Jamil Islam
- Civil and Environmental Engineering, South Dakota Mines, Rapid City 57701, SD, United States; BuG ReMeDEE consortium, South Dakota Mines, Rapid City 57701, SD, United States
| | - Venkataramana Gadhamshetty
- Civil and Environmental Engineering, South Dakota Mines, Rapid City 57701, SD, United States; BuG ReMeDEE consortium, South Dakota Mines, Rapid City 57701, SD, United States; 2-Dimensional Materials for Biofilm Engineering Science and Technology (2DBEST) Center, South Dakota School of Mines and Technology, Rapid City 57701, SD, United States.
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241
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Reis PCJ, Ruiz-González C, Crevecoeur S, Soued C, Prairie YT. Rapid shifts in methanotrophic bacterial communities mitigate methane emissions from a tropical hydropower reservoir and its downstream river. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 748:141374. [PMID: 32823225 DOI: 10.1016/j.scitotenv.2020.141374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/27/2020] [Accepted: 07/28/2020] [Indexed: 06/11/2023]
Abstract
Methane-oxidizing bacteria (MOB) present in the water column mitigate methane (CH4) emissions from hydropower complexes to the atmosphere. By creating a discontinuity in rivers, dams cause large environmental variations, including in CH4 and oxygen concentrations, between upstream, reservoir, and downstream segments. Although highest freshwater methanotrophic activity is often detected at low oxygen concentrations, CH4 oxidation in well-oxygenated downstream rivers below dams has also been reported. Here we combined DNA and RNA high-throughput sequencing with microscopic enumeration (by CARD-FISH) and biogeochemical data to investigate the abundance, composition, and potential activity of MOB taxa from upstream to downstream waters in the tropical hydropower complex Batang Ai (Malaysia). High relative abundance of MOB (up to 61% in 16S rRNA sequences and 19% in cell counts) and enrichment of stable isotopic signatures of CH4 (up to 0‰) were detected in the hypoxic hypolimnion of the reservoir and in the outflowing downstream river. MOB community shifts along the river-reservoir system reflected environmental sorting of taxa and an interrupted hydrologic connectivity in which downstream MOB communities resembled reservoir's hypolimnetic communities but differed from upstream and surface reservoir communities. In downstream waters, CH4 oxidation was accompanied by fast cell growth of particular MOB taxa. Our results suggest that rapid shifts in active MOB communities allow the mitigation of CH4 emissions from different zones of hydropower complexes, including in quickly re-oxygenated rivers downstream of dams.
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Affiliation(s)
- Paula C J Reis
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada.
| | - Clara Ruiz-González
- Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar (ICM-CSIC), Barcelona, Spain
| | - Sophie Crevecoeur
- Canada Centre for Inland Waters, Water Science and Technology Branch - Watershed Hydrology and Ecology Research Division, Environment and Climate Change Canada, Burlington, ON, Canada
| | - Cynthia Soued
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada
| | - Yves T Prairie
- Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada
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242
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Euler S, Jeffrey LC, Maher DT, Mackenzie D, Tait DR. Shifts in methanogenic archaea communities and methane dynamics along a subtropical estuarine land use gradient. PLoS One 2020; 15:e0242339. [PMID: 33232349 PMCID: PMC7685437 DOI: 10.1371/journal.pone.0242339] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 10/30/2020] [Indexed: 02/01/2023] Open
Abstract
In coastal aquatic ecosystems, prokaryotic communities play an important role in regulating the cycling of nutrients and greenhouse gases. In the coastal zone, estuaries are complex and delicately balanced systems containing a multitude of specific ecological niches for resident microbes. Anthropogenic influences (i.e. urban, industrial and agricultural land uses) along the estuarine continuum can invoke physical and biochemical changes that impact these niches. In this study, we investigate the relative abundance of methanogenic archaea and other prokaryotic communities, distributed along a land use gradient in the subtropical Burnett River Estuary, situated within the Great Barrier Reef catchment, Australia. Microbiological assemblages were compared to physicochemical, nutrient and greenhouse gas distributions in both pore and surface water. Pore water samples from within the most urbanised site showed a high relative abundance of methanogenic Euryarchaeota (7.8% of all detected prokaryotes), which coincided with elevated methane concentrations in the water column, ranging from 0.51 to 0.68 μM at the urban and sewage treatment plant (STP) sites, respectively. These sites also featured elevated dissolved organic carbon (DOC) concentrations (0.66 to 1.16 mM), potentially fuelling methanogenesis. At the upstream freshwater site, both methane and DOC concentrations were considerably higher (2.68 μM and 1.8 mM respectively) than at the estuarine sites (0.02 to 0.66 μM and 0.39 to 1.16 mM respectively) and corresponded to the highest relative abundance of methanotrophic bacteria. The proportion of sulfate reducing bacteria in the prokaryotic community was elevated within the urban and STP sites (relative abundances of 8.0%– 10.5%), consistent with electron acceptors with higher redox potentials (e.g. O2, NO3-) being scarce. Overall, this study showed that ecological niches in anthropogenically altered environments appear to give an advantage to specialized prokaryotes invoking a potential change in the thermodynamic landscape of the ecosystem and in turn facilitating the generation of methane–a potent greenhouse gas.
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Affiliation(s)
- Sebastian Euler
- SCU GeoScience, Southern Cross University, Lismore, NSW, Australia
- * E-mail: ,
| | - Luke C. Jeffrey
- SCU GeoScience, Southern Cross University, Lismore, NSW, Australia
| | - Damien T. Maher
- SCU GeoScience, Southern Cross University, Lismore, NSW, Australia
- School of Environment, Science and Engineering, Southern Cross University, Lismore, NSW, Australia
| | - Derek Mackenzie
- SCU GeoScience, Southern Cross University, Lismore, NSW, Australia
| | - Douglas R. Tait
- SCU GeoScience, Southern Cross University, Lismore, NSW, Australia
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243
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He T, Yuan J, Luo J, Lindsey S, Xiang J, Lin Y, Liu D, Chen Z, Ding W. Combined application of biochar with urease and nitrification inhibitors have synergistic effects on mitigating CH 4 emissions in rice field: A three-year study. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 743:140500. [PMID: 32653704 DOI: 10.1016/j.scitotenv.2020.140500] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 06/11/2023]
Abstract
Biochar and inhibitors applications have been proposed for mitigating soil greenhouse gas emissions. However, how biochar, inhibitors and the combination of biochar and inhibitors affect CH4 emissions remains unclear in paddy soils. The objective of this study was to explore the effects of biochar application alone, and in combination with urease (hydroquinone) and nitrification inhibitors (dicyandiamide) on CH4 emissions and yield-scaled CH4 emissions during three rice growing seasons in the Taihu Lake region (Suzhou and Jurong), China. In Suzhou, N fertilization rates of 120-280 kg N ha-1 increased CH4 emissions compared to no N fertilization (Control) (P < 0.05), and the highest emission was observed at 240 kg N ha-1, possibly due to the increase in rice-derived organic carbon (C) substrates for methanogens. Biochar amendment combined with N fertilization reduced CH4 emissions by 13.2-27.1% compared with optimal N (ON, Suzhou) and conventional N application (CN-J, Jurong) (P < 0.05). This was related to the reduction in soil dissolved organic C and the increase in soil redox potential. Addition of urease and nitrification inhibitor (ONI) decreased CH4 emissions by 15.7% compared with ON treatment. Combined application of biochar plus urease, nitrification and double inhibitors further decreased CH4 emissions by 22.2-51.0% compared with ON and CN-J treatment. ON resulted in the highest yield-scaled CH4 emissions, while combined application of biochar alone and in combination with the inhibitors decreased yield-scaled CH4 emissions by 12.7-54.9% compared with ON and CN-J treatment (P < 0.05). The lowest yield-scaled CH4 emissions were observed under combined application of 7.5 t ha-1 biochar with both urease and nitrification inhibitors. These findings suggest that combined application of biochar and inhibitors could mitigate total CH4 and yield-scaled CH4 emissions in paddy fields in this region.
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Affiliation(s)
- Tiehu He
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Junji Yuan
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Jiafa Luo
- AgResearch Limited, Ruakura Research Centre, Hamilton 3240, New Zealand
| | - Stuart Lindsey
- AgResearch Limited, Ruakura Research Centre, Hamilton 3240, New Zealand
| | - Jian Xiang
- Co-Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Yongxin Lin
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Deyan Liu
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Zengming Chen
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Weixin Ding
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
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244
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Mo Y, Qi XE, Li A, Zhang X, Jia Z. Active Methanotrophs in Suboxic Alpine Swamp Soils of the Qinghai-Tibetan Plateau. Front Microbiol 2020; 11:580866. [PMID: 33281775 PMCID: PMC7689253 DOI: 10.3389/fmicb.2020.580866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Accepted: 10/22/2020] [Indexed: 11/29/2022] Open
Abstract
Methanotrophs are the only biofilters for reducing the flux of global methane (CH4) emissions in water-logged wetlands. However, adaptation of aerobic methanotrophs to low concentrations of oxygen and nitrogen in typical swamps, such as that of the Qinghai-Tibetan Plateau, is poorly understood. In this study, we show that Methylobacter-like methanotrophs dominate methane oxidation and nitrogen fixation under suboxic conditions in alpine swamp soils. Following incubation with 13C-CH4 and 15N-N2 for 90 days under suboxic conditions with repeated flushing using an inert gas (i.e., argon), microbial carbon and nitrogen turnover was measured in swamp soils at different depths: 0-20 cm (top), 40-60 cm (intermediate), and 60-80 cm (deep). Results show detectable methane oxidation and nitrogen fixation in all three soil depths. In particular, labeled carbon was found in CO2 enrichment (13C-CO2), and soil organic carbon (13C-SOC), whereas labeled nitrogen (15N) was detected in soil organic nitrogen (SON). The highest values of labeled isotopes were found at intermediate soil depths. High-throughput amplicon sequencing and Sanger sequencing indicated the dominance of Methylobacter-like methanotrophs in swamp soils, which comprised 21.3-24.0% of the total bacterial sequences, as measured by 13C-DNA at day 90. These results demonstrate that aerobic methanotroph Methylobacter is the key player in suboxic methane oxidation and likely catalyzes nitrogen fixation in swamp wetland soils in the Qinghai-Tibetan Plateau.
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Affiliation(s)
- Yongliang Mo
- College of Environmental Science and Engineering, China West Normal University, Nanchong, China
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Xing-e Qi
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Aorui Li
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Xinfang Zhang
- School of Life Sciences, Lanzhou University, Lanzhou, China
| | - Zhongjun Jia
- State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
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245
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Li Y, Wang J, Hua M, Yao X, Zhao Y, Hu J, Xi C, Hu B. Strategy for denitrifying anaerobic methane-oxidizing bacteria growing under the oxygen-present condition. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 742:140476. [PMID: 32629252 DOI: 10.1016/j.scitotenv.2020.140476] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 06/11/2023]
Abstract
Denitrifying anaerobic methane oxidizing (DAMO) bacteria are newly discovered microorganisms that use methane as the electron donor to reduce nitrite into dinitrogen. They have potential value on nitrogen removal from wastewater. However, the oxygen exposure in engineering is considered one of the bottlenecks for DAMO engineering application. In this work, we cultured DAMO bacteria under oxic and anoxic conditions in a gas-lift sequencing batch reactor (GLSBR) to explore DAMO bacterial response to oxygen stress. Under oxic conditions (7.5-8 mg O2/L), the extension of hydraulic retention time (HRT) from 2 days to 4 days increased DAMO bacterial abundance by 3.8 times. Under anoxic conditions (0.2-0.5 mg O2/L), DAMO bacterial abundance increased by 30.1 times and were kept over 2.0 × 1011 copies g-1 wet sludge. During the enrichment, microbial aggregates were formed and DAMO bacteria tended to be distributed inside the aggregates. Notably, aerobic methanotrophs existed in the whole process, capable of consuming oxygen and providing a suitable environment for DAMO bacterial growth. Finally, DAMO bacteria were enriched and the relative abundance was 16.16%. This work provides new insights into DAMO bacterial enrichment and their application in wastewater treatment.
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Affiliation(s)
- Yufen Li
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiaqi Wang
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Miaolian Hua
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Xiangwu Yao
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yuxiang Zhao
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jiajie Hu
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China
| | - Chuanwu Xi
- Department of Environmental Health Sciences, School of Public Health, University of Michigan, Ann Arbor, MI, USA
| | - Baolan Hu
- Department of Environmental Engineering, College of Environmental &Resource Sciences, Zhejiang University, Hangzhou 310058, China; Zhejiang Province Key Laboratory for Water Pollution Control and Environmental Safety, Hangzhou 310058, China.
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246
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Methane Monooxygenase Gene Transcripts as Quantitative Biomarkers of Methanotrophic Activity in Methylosinus trichosporium OB3b. Appl Environ Microbiol 2020; 86:AEM.01048-20. [PMID: 32948519 DOI: 10.1128/aem.01048-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 09/10/2020] [Indexed: 01/20/2023] Open
Abstract
Methanotrophic microorganisms are characterized by their ability to oxidize methane. Globally they have a significant impact on methane emissions by attenuating net methane fluxes to the atmosphere in natural and engineered systems, though the populations are dynamic in their activity level in soils and waters. Methanotrophs oxidize methane using methane monooxygenase (MMO) enzymes, and selected subunit genes of the most common MMOs, specifically pmoA and mmoX, are used as biomarkers for the presence and abundance of populations of bacterial methanotrophs. The relative expression of these biomarker genes is dependent on copper-to-biomass ratios. Empirically derived quantitative relationships between methane oxidation biomarker transcript amounts and methanotrophic activity could facilitate determination of methane oxidation rates. In this study, pure cultures of a model type II methanotroph, Methylosinus trichosporium OB3b, were grown in hollow-fiber membrane bioreactors (HFMBR) under different steady-state methane oxidation conditions. Methanotroph biomass (DNA based) and methane oxidation biomarker mRNA transcript amounts were determined using quantitative PCR (qPCR) and reverse transcription-PCR (RT-qPCR), respectively. Under both copper-present and copper-limited conditions, per-cell pmoA mRNA transcript levels positively correlated with measured per-cell methane oxidation rates across 3 orders of magnitude. These correlations, if maintained across different methanotrophs, could prove valuable for inferring in situ oxidation rates of methanotrophs and understanding the dynamics of their impact on net methane emissions.IMPORTANCE Methanotrophs are naturally occurring microorganisms capable of oxidizing methane and have an impact on global net methane emissions. The genes pmoA and mmoX are used as biomarkers for bacterial methanotrophs. Quantitative relationships between transcript amounts of these genes and methane oxidation rates could facilitate estimation of methanotrophic activity. In this study, a strong correlation was observed between per-cell pmoA transcript levels and per-cell methane oxidation rates for pure cultures of the aerobic methanotroph M. trichosporium OB3b grown in bioreactors. If similar relationships exist across different methanotrophs, they could prove valuable for inferring in situ oxidation rates of methanotrophs and better understanding their impact on net methane emissions.
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Chiri E, Greening C, Lappan R, Waite DW, Jirapanjawat T, Dong X, Arndt SK, Nauer PA. Termite mounds contain soil-derived methanotroph communities kinetically adapted to elevated methane concentrations. THE ISME JOURNAL 2020; 14:2715-2731. [PMID: 32709975 PMCID: PMC7784690 DOI: 10.1038/s41396-020-0722-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 07/07/2020] [Accepted: 07/15/2020] [Indexed: 01/29/2023]
Abstract
Termite mounds have recently been confirmed to mitigate approximately half of termite methane (CH4) emissions, but the aerobic CH4 oxidising bacteria (methanotrophs) responsible for this consumption have not been resolved. Here, we describe the abundance, composition and CH4 oxidation kinetics of the methanotroph communities in the mounds of three distinct termite species sampled from Northern Australia. Results from three independent methods employed show that methanotrophs are rare members of microbial communities in termite mounds, with a comparable abundance but distinct composition to those of adjoining soil samples. Across all mounds, the most abundant and prevalent methane monooxygenase sequences were affiliated with upland soil cluster α (USCα), with sequences homologous to Methylocystis and tropical upland soil cluster (TUSC) also detected. The reconstruction of a metagenome-assembled genome of a mound USCα representative highlighted the metabolic capabilities of this group of methanotrophs. The apparent Michaelis-Menten kinetics of CH4 oxidation in mounds were estimated from in situ reaction rates. Methane affinities of the communities were in the low micromolar range, which is one to two orders of magnitude higher than those of upland soils, but significantly lower than those measured in soils with a large CH4 source such as landfill cover soils. The rate constant of CH4 oxidation, as well as the porosity of the mound material, were significantly positively correlated with the abundance of methanotroph communities of termite mounds. We conclude that termite-derived CH4 emissions have selected for distinct methanotroph communities that are kinetically adapted to elevated CH4 concentrations. However, factors other than substrate concentration appear to limit methanotroph abundance and hence these bacteria only partially mitigate termite-derived CH4 emissions. Our results also highlight the predominant role of USCα in an environment with elevated CH4 concentrations and suggest a higher functional diversity within this group than previously recognised.
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Affiliation(s)
- Eleonora Chiri
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, VIC, 3121, Australia
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia.
| | - Rachael Lappan
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - David W Waite
- School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - Thanavit Jirapanjawat
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
- School of Biological Sciences, Monash University, Clayton, VIC, 3800, Australia
| | - Xiyang Dong
- School of Marine Sciences, Sun Yat-Sen University, Zhuhai, 519082, China
| | - Stefan K Arndt
- School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, VIC, 3121, Australia.
| | - Philipp A Nauer
- School of Ecosystem and Forest Sciences, University of Melbourne, Richmond, VIC, 3121, Australia
- School of Chemistry, Monash University, Clayton, VIC, 3800, Australia
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Sousi M, Liu G, Salinas-Rodriguez SG, Chen L, Dusseldorp J, Wessels P, Schippers JC, Kennedy MD, van der Meer W. Multi-parametric assessment of biological stability of drinking water produced from groundwater: Reverse osmosis vs. conventional treatment. WATER RESEARCH 2020; 186:116317. [PMID: 32841931 DOI: 10.1016/j.watres.2020.116317] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 08/16/2020] [Accepted: 08/17/2020] [Indexed: 06/11/2023]
Abstract
Although water produced by reverse osmosis (RO) filtration has low bacterial growth potential (BGP), post-treatment of RO permeate, which is necessary prior to distribution and human consumption, needs to be examined because of the potential re-introduction of nutrients/contaminants. In this study, drinking water produced from anaerobic groundwater by RO and post-treatment (ion exchange, calcite contactors, and aeration) was compared with that produced by conventional treatment comprising (dry) sand filtration, pellet softening, rapid sand filtration, activated carbon filtration, and UV disinfection. The multi-parametric assessment of biological stability included bacterial quantification, nutrient concentration and composition as well as bacterial community composition and diversity. Results showed that RO permeate remineralised in the laboratory has an extremely low BGP (50 ± 12 × 103 ICC/mL), which increased to 130 ± 10 × 103 ICC/mL after site post-treatment. Despite the negative impact of post-treatment, the BGP of the finished RO-treated water was >75% lower than that of conventionally treated water. Organic carbon limited bacterial growth in both RO-treated and conventionally treated waters. The increased BGP in RO-treated water was caused by the re-introduction of nutrients during post-treatment. Similarly, OTUs introduced during post-treatment, assigned to the phyla of Proteobacteria and Bacteroidetes (75-85%), were not present in the source groundwater. Conversely, conventionally treated water shared some OTUs with the source groundwater. It is clear that RO-based treatment achieved an extremely low BGP, which can be further improved by optimising post-treatment, such as using high purity calcite. The multi-parametric approach adopted in this study can offer insights into growth characteristics including limiting nutrients (why) and dominating genera growing (who), which is essential to manage microbiological water quality in water treatment and distribution systems.
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Affiliation(s)
- Mohaned Sousi
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, AX Delft 2611, the Netherlands; Faculty of Science and Technology, University of Twente, Drienerlolaan 5, NB Enschede 7522, the Netherlands
| | - Gang Liu
- Key Laboratory of Drinking Water Science and Technology, Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, PR China; Department of Water Management, Faculty of Civil Engineering and Geoscience, Delft University of Technology, Mekelweg 2, CD Delft 2628, the Netherlands.
| | - Sergio G Salinas-Rodriguez
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, AX Delft 2611, the Netherlands
| | - Lihua Chen
- Department of Water Management, Faculty of Civil Engineering and Geoscience, Delft University of Technology, Mekelweg 2, CD Delft 2628, the Netherlands
| | - Jos Dusseldorp
- Oasen Drinkwater, Nieuwe Gouwe O.Z. 3, SB Gouda 2801, the Netherlands
| | - Peter Wessels
- Oasen Drinkwater, Nieuwe Gouwe O.Z. 3, SB Gouda 2801, the Netherlands
| | - Jan C Schippers
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, AX Delft 2611, the Netherlands
| | - Maria D Kennedy
- Department of Environmental Engineering and Water Technology, IHE Delft Institute for Water Education, Westvest 7, AX Delft 2611, the Netherlands; Department of Water Management, Faculty of Civil Engineering and Geoscience, Delft University of Technology, Mekelweg 2, CD Delft 2628, the Netherlands
| | - Walter van der Meer
- Faculty of Science and Technology, University of Twente, Drienerlolaan 5, NB Enschede 7522, the Netherlands; Oasen Drinkwater, Nieuwe Gouwe O.Z. 3, SB Gouda 2801, the Netherlands
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Ruiz-Ruiz P, Gómez-Borraz TL, Revah S, Morales M. Methanotroph-microalgae co-culture for greenhouse gas mitigation: Effect of initial biomass ratio and methane concentration. CHEMOSPHERE 2020; 259:127418. [PMID: 32574848 DOI: 10.1016/j.chemosphere.2020.127418] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/16/2020] [Accepted: 06/13/2020] [Indexed: 06/11/2023]
Abstract
This work evaluated the effect of different initial biomass ratios in a co-culture of an alkaliphilic methanotrophic bacteria consortium (AMB) and the green microalga Scenedesmus obtusiusculus (GM) on the maximum CH4 specific biodegradation rate and global carbon uptake. The highest maximum specific biodegradation rate was 589 ± 0.01 mgCH4 gbiomass-1 d-1 obtained for a proportion of 3:1 AMB-GM (w w-1) and 8% of initial CH4 in the headspace. The methane degradation rate was 1.5 times lower than the value obtained solely by the AMB consortium, and it was associated with pH increases due to the evolved CO2 consumption by the microalga. Increased activity of the AMB consortium along the experiments was due to progressive adaptation. Massive sequencing revealed the presence of methanotrophic/methylotrophic species such as Methylocystis sp., Methylomicrobium sp., Methylophaga sp., and Hyphomicrobium sp. Successful complete methane and carbon dioxide uptake was obtained with the 3:1, 4:1, and 5:1 AMB-GM biomass ratios, while for the rest of the ratios tested, more than 70% of the initial methane was transformed into biomass and inorganic carbon. This study showed that methanotrophic-microalgal co-cultures lead to a promising strategy for greenhouse gases mitigation in one step.
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Affiliation(s)
- Patricia Ruiz-Ruiz
- Doctorado en Ciencias Naturales e Ingeniería, Universidad Autónoma Metropolitana-Cuajimalpa, Cd. de México, Mexico
| | - Tania L Gómez-Borraz
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Av. Vasco de Quiroga 4871, colonia Santa Fe Cuajimalpa, C.P. 05300, Cd. de México, Mexico
| | - Sergio Revah
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Av. Vasco de Quiroga 4871, colonia Santa Fe Cuajimalpa, C.P. 05300, Cd. de México, Mexico.
| | - Marcia Morales
- Departamento de Procesos y Tecnología, Universidad Autónoma Metropolitana-Cuajimalpa, Av. Vasco de Quiroga 4871, colonia Santa Fe Cuajimalpa, C.P. 05300, Cd. de México, Mexico.
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Metatranscriptomics by
In Situ
RNA Stabilization Directly and Comprehensively Revealed Episymbiotic Microbial Communities of Deep-Sea Squat Lobsters. mSystems 2020; 5:5/5/e00551-20. [PMID: 33024051 PMCID: PMC8534475 DOI: 10.1128/msystems.00551-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Shinkaia crosnieri is an invertebrate that inhabits an area around deep-sea hydrothermal vents in the Okinawa Trough in Japan by harboring episymbiotic microbes as the primary nutrition. To reveal physiology and phylogenetic composition of the active episymbiotic populations, metatranscriptomics is expected to be a powerful approach. However, this has been hindered by substantial perturbation (e.g., RNA degradation) during time-consuming retrieval from the deep sea. Here, we conducted direct metatranscriptomic analysis of S. crosnieri episymbionts by applying in situ RNA stabilization equipment. As expected, we obtained RNA expression profiles that were substantially different from those obtained by conventional metatranscriptomics (i.e., stabilization after retrieval). The episymbiotic community members were dominated by three orders, namely, Thiotrichales, Methylococcales, and Campylobacterales, and the Campylobacterales members were mostly dominated by the Sulfurovum genus. At a finer phylogenetic scale, the episymbiotic communities on different host individuals shared many species, indicating that the episymbionts on each host individual are not descendants of a few founder cells but are horizontally exchanged. Furthermore, our analysis revealed the key metabolisms of the community: two carbon fixation pathways, a formaldehyde assimilation pathway, and utilization of five electron donors (sulfide, thiosulfate, sulfur, methane, and ammonia) and two electron accepters (oxygen and nitrate/nitrite). Importantly, it was suggested that Thiotrichales episymbionts can utilize intercellular sulfur globules even when sulfur compounds are not usable, possibly also in a detached and free-living state. IMPORTANCE Deep-sea hydrothermal vent ecosystems remain mysterious. To depict in detail the enigmatic life of chemosynthetic microbes, which are key primary producers in these ecosystems, metatranscriptomic analysis is expected to be a promising approach. However, this has been hindered by substantial perturbation (e.g., RNA degradation) during time-consuming retrieval from the deep sea. In this study, we conducted direct metatranscriptome analysis of microbial episymbionts of deep-sea squat lobsters (Shinkaia crosnieri) by applying in situ RNA stabilization equipment. Compared to conventional metatranscriptomics (i.e., RNA stabilization after retrieval), our method provided substantially different RNA expression profiles. Moreover, we discovered that S. crosnieri and its episymbiotic microbes constitute complex and resilient ecosystems, where closely related but various episymbionts are stably maintained by horizontal exchange and partly by their sulfur storage ability for survival even when sulfur compounds are not usable, likely also in a detached and free-living state.
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